add WIP for experimental source and sink objects
simplify the sink code a little
fix verbose printing
base class for compressed sinks
refactor into CompressedFPSource
PlainFPSink
update the documentation a little
fix spurious comma
fix invalid syntax
Merge branch 'feature/experimental_source_and_sink' into feature/append

merge for good measure, before it becomes too hard to merge

* feature/experimental_source_and_sink:
  update the documentation a little
  PlainFPSink
  refactor into CompressedFPSource
  base class for compressed sinks
  fix verbose printing
  simplify the sink code a little
  add WIP for experimental source and sink objects

Conflicts:
	bloscpack.py