emacs: remove Solarized for now

Will restore it when theme installation is managed with boxen.
emacs: switch to Source Code Pro typeface

...and only set font when run as Emacs.app.
emacs: start server automatically
emacs: modularize
emacs: recursive theme load path
emacs: use Solarized Dark if available
emacs: style cursor to match Terminal.app
emacs: hide menu in terminal mode