Support multipart gopaths

* Fixes #22
Display warning for aliased dependency not of type git-clone
Cleanup output
Check gopath at startup
Clear the cache and exit when passed --clear-cache
Update Readme
Bump version after changes to --clear-cache
Change Copyright message to 2013-2014
Update Copyright notice in LICENSE
Merge pull request #23 from vube/feature-multi-gopath

Feature multi gopath