Rebound `projectile-compile-project` to `C-c p c`
Rework project compilation

This addresses some of the issues raised in #98.  Basically now it's
easier to override default compile/test commands and project compile behaves
similarly to the stock `compile` command.

Note that this is work in progress and more changes are inbound.
Remove unneeded cl library
Revert "Remove unneeded cl library"

This reverts commit 6d01ffe3750b7618217ed2f73e03a754cceb8316.
Proper support for make projects