Added FileUploadParser refs #7
Tests for FileUploadParser
Codebase improvements on FileUploadParser

* Added docstrings.
* Added `FileUploadParser.get_filename` to make it easier to override.
* Added url kwargs filename detection step.
* Updated tests corresponding to these changes.
Raise ParseError if can't handle the uploaded file
Docs for FileUploadParser
Merge pull request #806 from wronglink/master

Added FileUploadParser