Add license file

This code has been made available according to the terms of the
MIT/Expat license; this adds a LICENSE file stating those terms.
Add MIT/Expat license boilerplate
Fix copy/pasto
Files under cram/ are BSD-licensed

Note in LICENSE that files in cram/* are licensed according to the
Modified (i.e., 3-clause) BSD license, which is mostly equivalent to
the MIT/Expat license.

Update copyright years in cram_decode.c and cram_io.h.
faidx: new faidx_has_seq() call
faidx: Fixed copy-and-paste documentation error
hts_file_type: correct return of FT_VCF_GZ
Merge pull request #113 from mcshane/feature/hts_file_type_fix

hts_file_type: correct return of FT_VCF_GZ
Don't call freeaddrinfo() when getaddrinfo() fails

POSIX is somewhat unclear here, but doing so segfaults on some
platforms.  Hat tip Kamil Slowikowski @slowkow.

Instead print a more detailed error message using gai_strerror().

[Cherry-picked from patch submitted to upstream klib.]
Bug fix in bcf_trim_alleles()
mpileup: Support for cigar operation N
Rationalise include guard macro names

Add a HTSLIB_ prefix to avoid conflicting with user code.
Avoid using the __ prefix reserved for the compiler implementation.
Ensure installation directories are world-executable

As for installed files, create leaf installation directories
without regard to umask.  (However any parent directories created
via  mkdir -p  will still have umask applied.)
Add copyright notices and licensing boilerplate

Functions kf_lgamma(), kf_erfc(), kf_gammap(), kf_gammaq(), kf_betai_aux(),
and the functions they call are from klib's kmath.c/.h written by Attractive
Chaos.  kt_fisher_exact() and the functions it calls are from the previous
(standalone) samtools's bcftools/fet.c, written by Heng Li.

Also rationalise kfunc.h's include guard macro name.  Eventually these
may be replaced by upstream kmath.c/.h (augmented with kt_fisher_exact())
with its AC_KMATH_H guard.
Add klib copyright notices and licensing boilerplate

For knetfile.h, copy boilerplate from knetfile.c (the same copyright
years apply to knetfile.h).  Add appropriate copyright years to the
kstring.h notice, and copy the resulting boilerplate to kstring.c
(where the same copyright years again apply).

Other klib files already have appropriate notices and boilerplate.

Remove kstdint.h, which is unused in htslib/samtools/bcftools,
and remove it from htslib.mk.
Omit control files and README.md from release tarballs
Add copyright notices and licensing boilerplate
Add copyright notices and licensing boilerplate

(There is also a small contribution from Joel Thibault that is not
legally significant for copyright purposes.)
Update copyright notices to reflect historic changes

In bgzf.c, add 2012 to parallel the related notice in bgzf.h.
Add Genome Research notice pertaining to changes from Heng Li in 2009
and from others in more recent years.
Add copyright notices and licensing boilerplate

These files originated in the tabix project as tabix.h (htslib/tbx.h)
and index.c (tbx.c).  Early copyright years have been taken from the
copyright notice in tabix/tabix.h, which records that this code originated
while its author was at Sanger in 2009 and was further modified while he
was at Broad in 2010.  Later copyright years from 2012 onwards relate to
the files' histories within this htslib repository.

(See also https://github.com/samtools/tabix)