Lein 2 Compatibility

First pass at compatibility with Leiningen 2.
* Removes dependency on old contrib (throwf).
* Accounts for Leiningen namespace reorganization.
* Updates eval-in-project to match new (restricted) API.

Limitations:
* Can no longer spawn a background process directly since the ant-based callback has been removed from Leiningen (the .setSpawn call that lein-daemon used to do).
* Usage is now: `lein daemon start :process &` or `nohup lein daemon start :process &`
* `lein daemon stop :process` correctly kills the process but "clojure.lang.ExceptionInfo: Subprocess failed {:exit-code 143}" is displayed