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.

First real bug in it for years, its served me well.

- 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.