Add fancy indexing support for DOK item assignment

[DragaDoncila]

Modify __setitem__ to support a subset of advanced/fancy indexing where all dimensions are indexed. This uses @stschroe's gist here.

We also need __getitem__, but we thought we'd submit that as a separate PR.

[codecov]

Codecov Report

Merging #435 (8a71345) into master (440809f) will increase coverage by 0.09%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #435      +/-   ##
==========================================
+ Coverage   95.37%   95.46%   +0.09%     
==========================================
  Files          19       20       +1     
  Lines        2809     2846      +37     
==========================================
+ Hits         2679     2717      +38     
+ Misses        130      129       -1     

[hameerabbasi]

It would be nice to get the code coverage up -- Look into pytest.raises (there are uses in the tests) and try to hit everything and possibly remove dead code.

[DragaDoncila]

Hi @hameerabbasi I've added a few more tests and it looks like it's hitting 100% of the diff. Please let me know if there's anything else you'd like to see!

[hameerabbasi]

This should be the last change needed -- Sorry for the slow feedback loop.

[DragaDoncila]

Not slow at all! Thank you for the prompt reviews 😃

[hameerabbasi]

Thanks @DragaDoncila! This is in!