started implementing proper logging for #18
log to both console and file, for #18

also format info logs to the console like a normal print statment
For #18: updated args formatting to include values
Added logging functions for C++

For #18
Updated comments

For #18
For #18: fixed failing tests and corrected copywrite on new files I added
for #18: bamliquidator_regions now honors bamliquidator logging arguments

also samtools stderr logging is suppressed when in quiet mode.  this could possibly
lead to useful information being lossed, but this seems unlikely since samtool error
messages are usually pretty generic like the following:

  [bam_parse_region] fail to determine the sequence name.

and this would always lead to a line like the following in log.txt:

  2014-08-07 23:44:39 WARNING skipping region 2 (bam file key 1 chr33 MM1S_CTCF_11890 27130338 -> 27133471 . 0) due to error: bam_parse_region failed with return code -1

I'm not sure the "fail to determine the sequence name" is terribly helpful anyway.
For #18 bamliquidator_bins now honors bamliquidator_batch logging config
added version to counts.h5 file, resolves #23
Fixed test using undefined variable
Made abstract methods explicit
Fixed logging syntax error
Merge pull request #27 from BradnerLab/logfile

Logfile