updated khmer.file error messages
Merge remote-tracking branch 'origin' into cleanup/filepy

Conflicts:
	ChangeLog
updated khmer ref & copyright year
fixed copyright year
Merge pull request #483 from ged-lab/cleanup/filepy

some cleanup of file.py error messages & other minor updates.
updated reservoir sampling script to produce multiple subsamples with -S; added docs
add epilog to sample-reads-randomly.py
updated ChangeLog for multiple subsamples with sample-reads-randomly
updated epilog docstring per @mr-c
removed SHELL setting in Makefile
added long-form options; fixed epilog crashing bug by adding metavar
pep8
include script in documentation
100% coverage
Merge pull request #197 from ged-lab/reservoir_sampling2

updated reservoir sampling script to produce multiple subsamples
slim down the PyPI distribution