Preventing loss of classpath information on REPL start

This pull request adds `:eval-in :leiningen` to the project map passed to `leiningen.repl/repl`, probably causing `leiningen.core.eval/eval-in-project` to be executed inside the current instead of a child process (see [here](https://github.com/technomancy/leiningen/blob/master/leiningen-core/src/leiningen/core/eval.clj#L211)). This retains classpath information that seems to get lost if a subprocess is created.

This should thus fix issue #3.

(Also, I renamed `resolve-deps` to `resolve-try-deps!` and `add-deps` to `add-try-deps`, hope that's okay.)