incremental updates

Note that a change to vcfstreamsort ensures proper sorting by reference
position *and* variant representation.  Currently, does not handle the case in
which alleles at multiallelics are not sorted identically, so this should be
used after vcfbreakmulti for best results.
Provide much-needed overview of available functions in the README.md
directory restructuring, cleanup, documentation improvements

By (sanely) writing all executables to bin/, users can install by adding the
directory to their path.  This also cleans up the presentation on github,
which, due to my supreme laziness, functions as the only website describing the
library.

Links in README.md allow quick perusal of the documentation.  Hello Web 0.9!
further updates to README
more docs updates
resolve issue #20 per krttrr's suggestion

The expected behavior is to only use alternate genotypes.
updated tabixpp, resolving #11
edge case fix, numbers as strings in vcffilter

If a number is provided for comparison with a string, the comparison will fail
because it first checks if both the variables being compared have the same
type.  We can deal with this by checking if one is a string and the other a
number at comparison time, and converting both into strings for comparison.
This allows user-expected behavior when doing things like:

    vcffilter -f "Q = 2"

When Q is a string variable in the VCF file.
Fix finding overlaps with bed files
Merge pull request #23 from kevyin/master

Fix finding overlaps with bed files
Merge remote-tracking branch 'upstream/master'

Conflicts:
	Makefile