makefile: Added the "test" rule
To keep valgrind happy: free all malloc()ed memory at the end
pbwtMerge: Merge only records present in all files (intersection, not a union); Handle duplicate positions (for now assuming that records are sorted by the REF+ALT string)
Merge remote branch 'remotes/rd/master'
pbwtMerge: resolved merge conflict, renamed old "Update" struct to the new "PbwtCursor"
Merge pull request #2 from pd3/master

Changes in pbwtMerge - I hope it now compiles at least!
initial htslib code and linking
add pbwtHtslib.c
adding hooks into readVcf
Link htslib statically
A working example of -readVcf: reads VCF/BCF and prints chr:pos ref alt <GTs> <PLs>
merge of Petr's initial htslib completion
lots of changes
many edits including cleaned up interface for pbwtCursor and referencePhase().
referenceImpute() is unfinished/unfunctional as yet.
select and remove sites, referenceImpute and compareGenotypes (may be buggy), adding aFend to macs, vcf and gen parsing as now required by pbwtWrite