Initial proof of principle order independent data checksum
Remove xor of checksums
Merge remote-tracking branch 'upstream/master' into seqchksum

Conflicts:
	src/Makefile.am
Add struct for checksum data and methods
add chksums without name
Remove crc32_combine use (to revert slowdown)
first attempt at per readgroup checksums
Tabs rather than spaces in output
Checksum pass only data as well as all, default verbose off.
Add title line to output
Add man page for bamseqchksum
Flip internal order of struct to be consistent with output order
Remove superfluous includes and whitespace changes
incorrect title of man page
whitespace changes to fit with biobambam style
move internal class so that other program code is together
Allow sam and cram input using io_lib
assert that readgroups checksums are consistent with overall checksum

and add appropriate operator== methods to help do this
fourth checksum uses certain BAM aux tags
add and alter comments