Fixed URI encoding issue

 I'm getting a validation error on search parameters:

    $search->repositories('language:perl+created:>2014-08-28');
    # validation error

Reason is that GitHub API does not like the URL to be URI encoded. You can replicate in your browser:

fails:
https://api.github.com/search/repositories?q=language%3Aperl%2Bcreated%3A%3E2014-08-28

works:
https://api.github.com/search/repositories?q=language:perl+created:%3E2014-08-29

I patched Search.pm to replace the troublesome symbols.