Some cases fix

[edoardocavazza]

This PR fixes:

• the source pattern could match directories (eg: installing normalize.css using bower creates normalize.css folder)
• local file url should trim the hash part of the original url (eg: some icomoon fonts have the hash #icomoon in the url)

[mihhail-lapushkin]

• For the first issue. Grunt supports filtering by file type. No need to duplicate it in this plugin.
• About the hash. Isn't it there for a reason? If you strip it, won't something break?