[tmux] Remove powerline symbols, adjust to base16
[i3] Use FontAwesome for some i3 status bar fields
[zsh] Use $HOME when sourcing stuff instead of ~
[zsh] Load dircolors at start
[zsh] Change colors to fit base16 theme better.

Also make sure BASE16_* variables are loaded consistently and allow
nesting shells and working nicely with tmux.
[zsh] Load z at startup
[gitconfig] Update gitconfig
[ncmpcpp] Update ncmpcpp config
[xbindkeys] Use termite as default terminal
[zsh] Move zsh_vars to zshenv
[zsh] Update zshenv
[bin] Update bin/screens