support "hash" alias

[garak]

Bower is supporting definitions like this one:

"Ionicons": "ionicons#^2.0.1"

where the key is a sort of name alias, where the actuale package name is in the value, followed by an hash and finally the version. So, bowerphp should support this, checking for a possible hash, stripping everything before and assigning it to package name and keeping the rest (except the hash itsfelf) as version.
So, the resulting of previous example should work as if it was:

"ionicons": "^2.0.1"