Switch to use tangle/file everywhere. Lots of cleanup.

Also define option predicates via the makefile option of:

make option NAME=whatever

Which defines the options in options/whatever.el and
options/no-whatever.el

Switch from using osx-p to macos-p now for osx.

There were a few other changes that snuck in that I was too
lazy to split apart. But all this should make this all simpler.

It also means you can edit source blocks in emacs sanely.

- Added default shell to be zsh -l for login
- Made xclip stuff not show up on osx tmux.conf

rtags is not working on osx, and idris is failing to compile.

Ain't got time to fix/debug right now. Later.