Add support for nested dirs inside src/

When having nested directories (for instance `src/protocol/tm_protocol.erl`)
autocompilation would fail. This fix adds the abspath of all depdencies to
the codepath and sets compile option {i, _} to support both `deps/` and `lib/`.
Merge pull request #620 from lafka/erl-nested-dirs

Add support for nested dirs inside src/