[MRG] Add deduction of ksize from query

[betatim]

Fixes #105

When the query only contains one k-size then use that unless
user specified a particular k. Same when there is only one molecule type.

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[codecov-io]

Codecov Report

Merging #119 into master will decrease coverage by 0.16%.
The diff coverage is 76.47%.

@@            Coverage Diff             @@
##           master     #119      +/-   ##
==========================================
- Coverage    85.6%   85.44%   -0.17%     
==========================================
  Files          13       13              
  Lines        1897     1903       +6     
  Branches       52       52              
==========================================
+ Hits         1624     1626       +2     
- Misses        262      266       +4     
  Partials       11       11

Impacted Files	Coverage Δ
sourmash_lib/sourmash_args.py	93.42% <100%> (+0.17%)	⬆️
sourmash_lib/commands.py	89.4% <71.42%> (-0.56%)	⬇️

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[ctb]

Note addition of load_one_signature in #155.

[betatim]

I'll think again about load_one_signature, though it seems right now we do Ok with the existing loaders. They all seem to error when there is ambiguity.

[betatim]

Need to investigate why codecov thinks this line isn't covered

[ctb]

On Wed, Apr 12, 2017 at 01:10:07AM -0700, Tim Head wrote: I'll think again about `load_one_signature`, though it seems right now we do Ok with the existing loaders. They all seem to error when there is ambiguity.

load_one_signature is primarily designed for my use at command line and in little scripts, but by my understanding it should reduce some code and the use of assert statements in commands.py, too.

[betatim]

Refreshed this.

Still not quite sure how to modify this to use load_one_signature :-/

[ctb]

Refresh this and I'll merge.

Note: may fix #189 too.

[ctb]

Also note: if you make these branches on the dib-lab repo I can refresh...

[betatim]

Sorry about the foreign branch, keep forgetting.

[ctb]

Updated in #224 - might as well just merge that one, I guess?

[luizirber]

Fixed by #224