Memory leak with getDataURL()

[Kruithne]

Within the codebase, we have a number of calls to getDataURL() on the BufferWrapper class, but the only place that we actually call revokeDataURL() is in the audio tab. Most of these calls come from the texture ribbon feature. As far as I can tell, the data being assigned to these URLs is never unassigned during the runtime of the application, resulting in a memory leak.