Many tmux.conf updates: SSH context, file layout, other minor tweaks.

Added color/context support for for windows, panes, and status bar when in ssh.
Fixed tmux statusbar format and uptime for remote SSH instances.
changed default git editor to vim from gvim for server compatibility.
Fixed tmux typo in SSH color choosing.
Fixed typo in tmux statusline; missing starting colors.
Submodule: updated zsh.