Put all terminal colours in to one file

This way they can be used/sourced by any program that wants to interact
with tmux, vim, etc
Get vim colours from the environment
Move tmux configuration to a bash script

This allows the use of `if` statements, environment variables, and
version checks
Add battery monitor to tmux config
Update linters.vim bundle
Make tmux conf work on old 1.6 versions
Make build_ps1.py more idiomatic
Only show battery status if we have a battery
Add some tmux bindings for window splitting, file editing
Add vim key bindings for home/end
Add script for updating dot files on other hosts

Invoke like '~/.dot-files/update-dot-files host1 host2 host3'