dump signature in text format

[ctb]

Prototype implementation of text dump format for MinHash sketches created by mash; see marbl#27.

[ctb]

The following now works:

./mash sketch -k 31 short.fa
./mash dump short.fa.msh short.fa.dump
~/dev/sourmash/mash-csv-to-sig.py short.fa.dump

this will put a sourmash signature file in <md5sum>.sig; you can now compare that signature to signatures computed from the murmur64 branch of sourmash, e.g.

~/dev/sourmash/sourmash compute -k 31 -n 1000 short.fa
~/dev/sourmash/sourmash compare -k 31 *.sig

yields

# running sourmash subcommand: compare
loading short.fa.sig
loading 9191284a.sig
0-            short.fa  [ 1.  1.]
1-            short.fa  [ 1.  1.]
min similarity in matrix: 1.0