2.1.1

This release provides bug fixes and modest improvements to
Bloom filter assembly contiguity/correctness. Parallelization
of Sealer has also been improved, thanks to contributions by
@vlad0x00.

abyss-bloom-dbg:

• upgrade to most recent version of ntHash to reduce
  some assembly/hashing artifacts. On a human assembly, this
  reduced QUAST major misassemblies by 5% and increased
  scaffold contiguity by 10%
• kc parameter now also applies to MPI assemblies (see below)

abyss-fac:

• change N20 and N80 to N25 and N75, respectively

ABYSS-P:

• add --kc option, with implements a hard minimum k-mer
  multiplicity cutoff

abyss-pe:

• fix zsh: no such option: pipefail error with
  old versions of zsh (fallback to bash instead)
• adding time=1 now times all assembly commands

abyss-sealer:

• parallelize gap sealing with OpenMP (thanks to
  @vlad0x00!)
• add --gap-file option (thanks to @vlad0x00!)

DistanceEst:

• add support for GFA output