RTFHandler: protect against CR and bad hexadecimal sequence

In RTF is possible to specify characters with the sequence \'XX being
XX an hexadecimal number.
With this changeset we guard against incorrect hexadecimal numbers which
will be ignored.

The other change added is to ignore carriadge returns in plain text.

Tests/Unit/Fixtures/bad_hex_and_cr.rtf

@@ -0,0 +1 @@
+{\rtf1\adeflang1025\ansi\ansicpg1252\uc1\adeff0\deff0\stshfdbch0\stshfloch37\stshfhich37\stshfbi37\deflang3082\deflangfe3082\themelang3082\themelangfe0\themelangcs0{\fonttbl{\f0\fbidi \froman\fcharset0\fprq2{\*\panose 02020603050405020304}Times New Roman;}{\f0\fbidi \froman\fcharset0\fprq2{\*\panose 02020603050405020304}Times New Roman;}{\f37\fbidi \fswiss\fcharset0\fprq2{\*\panose 020f0502020204030204}Calibri;}{\f31500\fbidi \froman\fcharset0\fprq2{\*\panose 02020603050405020304}Times New Roman;}{\f31501\fbidi \froman\fcharset0\fprq2{\*\panose 02020603050405020304}Times New Roman;}{\f31502\fbidi \froman\fcharset0\fprq2{\*\panose 02040503050406030204}Cambria;}{\f31503\fbidi \froman\fcharset0\fprq2{\*\panose 02020603050405020304}Times New Roman;}{\f31504\fbidi \froman\fcharset0\fprq2{\*\panose 02020603050405020304}Times New Roman;}{\f31505\fbidi \froman\fcharset0\fprq2{\*\panose 02020603050405020304}Times New Roman;}{\f31506\fbidi \fswiss\fcharset0\fprq2{\*\panose 020f0502020204030204}Calibri;}{\f31507\fbidi \froman\fcharset0\fprq2{\*\panose 02020603050405020304}Times New Roman;}{\f39\fbidi \froman\fcharset238\fprq2 Times New Roman CE;}{\f40\fbidi \froman\fcharset204\fprq2 Times New Roman Cyr;}{\f42\fbidi \froman\fcharset161\fprq2 Times New Roman Greek;}{\f43\fbidi \froman\fcharset162\fprq2 Times New Roman Tur;}{\f44\fbidi \froman\fcharset177\fprq2 Times New Roman (Hebrew);}{\f45\fbidi \froman\fcharset178\fprq2 Times New Roman (Arabic);}{\f46\fbidi \froman\fcharset186\fprq2 Times New Roman Baltic;}{\f47\fbidi \froman\fcharset163\fprq2 Times New Roman (Vietnamese);}{\f39\fbidi \froman\fcharset238\fprq2 Times New Roman CE;}{\f40\fbidi \froman\fcharset204\fprq2 Times New Roman Cyr;}{\f42\fbidi \froman\fcharset161\fprq2 Times New Roman Greek;}{\f43\fbidi \froman\fcharset162\fprq2 Times New Roman Tur;}{\f44\fbidi \froman\fcharset177\fprq2 Times New Roman (Hebrew);}{\f45\fbidi \froman\fcharset178\fprq2 Times New Roman (Arabic);}{\f46\fbidi \froman\fcharset186\fprq2 Times New Roman Baltic;}{\f47\fbidi \froman\fcharset163\fprq2 Times New Roman (Vietnamese);}{\f409\fbidi \fswiss\fcharset238\fprq2 Calibri CE;}{\f410\fbidi \fswiss\fcharset204\fprq2 Calibri Cyr;}{\f412\fbidi \fswiss\fcharset161\fprq2 Calibri Greek;}{\f413\fbidi \fswiss\fcharset162\fprq2 Calibri Tur;}{\f416\fbidi \fswiss\fcharset186\fprq2 Calibri Baltic;}{\f417\fbidi \fswiss\fcharset163\fprq2 Calibri (Vietnamese);}{\f31508\fbidi \froman\fcharset238\fprq2 Times New Roman CE;}{\f31509\fbidi \froman\fcharset204\fprq2 Times New Roman Cyr;}{\f31511\fbidi \froman\fcharset161\fprq2 Times New Roman Greek;}{\f31512\fbidi \froman\fcharset162\fprq2 Times New Roman Tur;}{\f31513\fbidi \froman\fcharset177\fprq2 Times New Roman (Hebrew);}{\f31514\fbidi \froman\fcharset178\fprq2 Times New Roman (Arabic);}{\f31515\fbidi \froman\fcharset186\fprq2 Times New Roman Baltic;}{\f31516\fbidi \froman\fcharset163\fprq2 Times New Roman (Vietnamese);}{\f31518\fbidi \froman\fcharset238\fprq2 Times New Roman CE;}{\f31519\fbidi \froman\fcharset204\fprq2 Times New Roman Cyr;}{\f31521\fbidi \froman\fcharset161\fprq2 Times New Roman Greek;}{\f31522\fbidi \froman\fcharset162\fprq2 Times New Roman Tur;}{\f31523\fbidi \froman\fcharset177\fprq2 Times New Roman (Hebrew);}{\f31524\fbidi \froman\fcharset178\fprq2 Times New Roman (Arabic);}{\f31525\fbidi \froman\fcharset186\fprq2 Times New Roman Baltic;}{\f31526\fbidi \froman\fcharset163\fprq2 Times New Roman (Vietnamese);}{\f31528\fbidi \froman\fcharset238\fprq2 Cambria CE;}{\f31529\fbidi \froman\fcharset204\fprq2 Cambria Cyr;}{\f31531\fbidi \froman\fcharset161\fprq2 Cambria Greek;}{\f31532\fbidi \froman\fcharset162\fprq2 Cambria Tur;}{\f31535\fbidi \froman\fcharset186\fprq2 Cambria Baltic;}{\f31536\fbidi \froman\fcharset163\fprq2 Cambria (Vietnamese);}{\f31538\fbidi \froman\fcharset238\fprq2 Times New Roman CE;}{\f31539\fbidi \froman\fcharset204\fprq2 Times New Roman Cyr;}{\f31541\fbidi \froman\fcharset161\fprq2 Times New Roman Greek;}{\f31542\fbidi \froman\fcharset162\fprq2 Times New Roman Tur;}{\f31543\fbidi \froman\fcharset177\fprq2 Times New Roman (Hebrew);}{\f31544\fbidi \froman\fcharset178\fprq2 Times New Roman (Arabic);}{\f31545\fbidi \froman\fcharset186\fprq2 Times New Roman Baltic;}{\f31546\fbidi \froman\fcharset163\fprq2 Times New Roman (Vietnamese);}{\f31548\fbidi \froman\fcharset238\fprq2 Times New Roman CE;}{\f31549\fbidi \froman\fcharset204\fprq2 Times New Roman Cyr;}{\f31551\fbidi \froman\fcharset161\fprq2 Times New Roman Greek;}{\f31552\fbidi \froman\fcharset162\fprq2 Times New Roman Tur;}{\f31553\fbidi \froman\fcharset177\fprq2 Times New Roman (Hebrew);}{\f31554\fbidi \froman\fcharset178\fprq2 Times New Roman (Arabic);}{\f31555\fbidi \froman\fcharset186\fprq2 Times New Roman Baltic;}{\f31556\fbidi \froman\fcharset163\fprq2 Times New Roman (Vietnamese);}{\f31558\fbidi \froman\fcharset238\fprq2 Times New Roman CE;}{\f31559\fbidi \froman\fcharset204\fprq2 Times New Roman Cyr;}{\f31561\fbidi \froman\fcharset161\fprq2 Times New RoLine truncated

Tests/Unit/TestRTFHandler.m

@@ -306,4 +306,13 @@
                  againstExpectedHTML: expected];  
 }
 
+- (void) test_bad_hex_and_cr
+{
+  NSString *file =@"bad_hex_and_cr.rtf";
+  NSString *expected=@"<html><meta charset='utf-8'><body><font face=\"Calibri\"><font face=\"Calibri Cyr\"><font color=\"#000000\">Good hex:H Bad1Hex: Bad2Hex: Ignored Carriadge Return</font></font></font></body></html>";
+
+  [self checkHTMLConversionOfRTFFile: file
+                 againstExpectedHTML: expected];  
+}
+
 @end