Merge CRAM copyright notices and data race fixes from jkbonfield

Merge commit 116ccd228c128f95 of github.com/jkbonfield/htslib:

116ccd2 Fixed a variety of multi-threading data races
d3803f3 Fixed errors in copyright due to pasting the MRC one
b5f5f16 Added copyright notices.
Merge cram_set_header() from github.com/jkbonfield/htslib

f149e78 Added prototype for cram_set_header()
808b36f [...] samtools interface needed an additional cram_set_header

Modified when merging to use cram_set_header() within sam_hdr_write(),
rather than using hts_open()'s old-API-style third parameter, which will
soon be disappearing.
Merge branch develop of github.com/jkbonfield/htslib

Robustness improvements indicated via clang's static analyser
and fuzz testing.