vim ftplugin settings for gitcommit and mail
new mail sig for more privacy
misc tweaks
mutt: explicit vim editor
gitconfig: cleanup
vim: plugins: rm unnecessary plugins
vim: move fugitive statusline config to gvimrc

This is because fugitive statusline does not apply to vim, but only to
gvim. As such, keeping this line in vimrc results in startup error when
loading vim as opposed to gvim