Add support to equal sign - '=' - on URL

[jaircuevajunior]

Updated filename regex pattern to allow the equal sign as being part of the filename portion of the route, otherwise it would fall on 404 error.

[olivervogel]

Can you elaborate, when this error occurs?

[jaircuevajunior]

Sure.
In this case I was using a base64 encoded string as filename (which sometimes ends with an equal sign).
I realized that when the equal sign is present on URL, the route is not recognized.
I'm using intervention/imagecache for this but the route is created in this package (intervention/image) service provider.

To clarify, for instance:

Let's take 'images/cache' as the imagecache route.
If I try to get images/cache/module_desk/uploads/module_avatar/KEQbRnXa47uqIFaEoUutsD98lqc5Rv-metaQmFubmVyLW1vYmlsZS5qcGc=-.jpg it doesn't work, because it fails the regex, so the route is not even called.