Implemented HTTPRangedByteAccess.

HTTPRangedByteAccess supports HTTP range requests for ranges of resources. Includes a test
that executes against a few bytes of the test mouse chromosome on the berkeley server.

(Matt or Frank, check out the additional test case in ByteAccessSuite, let me know if using the URL of the mouse_chrM.bam, which is the same bam as used in the integration tests, is okay here in the unit tests too.) 

This branch is a precursor to fixing the tests / integration tests on the big Parquet / RDD PR.
Ah, OK! Might make sense to clarify that in the comment, since people may not be familiar with a 206 code.