Time for a colourscheme change

This one has been in the works for several weeks. Have only really tested
it on one screen though so we'll see how it looks in other settings.
Vim: simpler colours, better linux terminal support
Vim: bind F-keys for frequent operations,
Vim: Hide binary files from tree, other fixes
Git: fix git-current-branch
More colourscheme simplification: vim and tmux