Adding some convenience bash functions for finding & killing procs

I know there's pgrep & pkill, but somehow I couldn't get them to find
those processes I was looking for (die, offlineimap)
adding vim module for Dash doc browser
making mutt f & F binding account specific, adding sidebar color
adding keymapping for switching between 2 and 4 spaces for indents
integrating tmux copying into system clipboard

h/t http://robots.thoughtbot.com/tmux-copy-paste-on-os-x-a-better-future
adding new mailbox folder