Clean up translation context prefixes.
While creating the German translation, I noticed:
- Gender strings are duplicated (male/female), once with a context prefix and once without.
- Some stuff needlessly has a context prefix (in general, anything that's on a Windows MessageBox - that is, abort/retry/ignore/help/ok/cancel/yes/no - needs no context prefix).
- Some code uses use ZCTX(_("unprefixed")) - no need to remove the context prefix if there isn't any to begin with!
Please get this fixed soon after 0.8 release.