support normal and insert mode cursor in tmux

Surround cursor escape sequences with the tmux DCS sequence to use a
different cursor in normal and insert mode.
cleanup tmux conf a bit after switching to iterm
ignore dropbox folders
ignore node folders
ignore vim netrw history
index from 1
consistently use 'set' for 'set-option'
add pathogen
add CommandT vim plugin
add vim-eunuch
add vim-ruby
add vim-commentary
use solarized vim color scheme