#44 gif support and minor additions

[HoverHell]

I've merged the svn trunk into my github mirror ( https://github.com/HoverHell/mcomix ); there are a couple features (such as solving the https://sourceforge.net/p/mcomix/feature-requests/93/ ) that could be merged back one way or another (e.g. by making a patch diff'ing with the corresponging svn commit).