This change means there can now be different translations for the same
english string depending on the context. It is based on gettext msgctxt feature.
There is a new macro _c(msg, ctxt) that should be used instead of _(msg) in
the source code when we want to add a context to the message. For the
moment I have added contexts to only one message ("None") so that I could
test the changes. Context could be added also to get shorter translations when
GUI is in 1x mode.
I have also added back the fuzzy option to msmerge since it is useful when
adding contexts to populate the translations for the new contexts.
svn-id: r52308
