Have File inherit from GenericBinary

[whyitfor]

While reviewing #469, I noticed that most Identifiers target File and GenericBinary. The impact of this is that OFRAK tries to run identifiers twice against any File: first it runs identifiers since it is a File, then re-runs the identifier when the GenericBinary tag is added.

Since all file's are binaries (by definition), it seems reasonable to refactor File as such:

class File(GenericBinary, FilesystemEntry)

and have identifiers only target GenericBinary

Which files would be affected?
Identifiers, and File.

Does the proposed maintenance include non-doc string functional changes to the Python code?
Perhaps

Are you interested in implementing it yourself?
Yes