The goal is to be able to use 'letter' releases such as '2.0.3a'
in the Version file.
SoObjects/Mailer/GNUmakefile.preamble: UIX_MAILER_*_VERSION are now strings
Can't use SOGoVersion since the etag uses an 'underscore' notation (2_0_3a)
SoObjects/Mailer/*.m: updated format for UIX_MAILER_*_VERSION
SoObjects/SOGo/GNUmakefile: zap SOGo_VERSION, unsused
SoObjects/SOGo/GNUmakefile.preamble: fix defines
UI/MainUI/SOGoRootPage.m: use SOGoVersion
ea26e0cc0a