Remove attrs dependence from immutablecollections

[berquist]

• [ ] Contains a change log entry for Towncrier (Should I do this even though the user interface hasn't changed?)

Closes https://github.com/isi-vista/immutablecollections/issues/37.

[codecov[bot]]

Codecov Report

Merging #38 into master will decrease coverage by 0.7%. The diff coverage is 86%.

@@            Coverage Diff             @@
##           master      #38      +/-   ##
==========================================
- Coverage   90.51%   89.81%   -0.71%     
==========================================
  Files           7        7              
  Lines         622      638      +16     
==========================================
+ Hits          563      573      +10     
- Misses         59       65       +6

Impacted Files	Coverage Δ
immutablecollections/_immutabledict.py	84.21% <100%> (ø)	:arrow_up:
immutablecollections/_immutablemultidict.py	91.09% <84.21%> (-0.9%)	:arrow_down:
immutablecollections/_immutableset.py	89.86% <85.71%> (-1.14%)	:arrow_down:

---

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Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update e7fe0bf...1905ad0. Read the comment docs.

[codecov[bot]]

Codecov Report

Merging #38 into master will decrease coverage by 0.7%. The diff coverage is 86%.

@@            Coverage Diff             @@
##           master      #38      +/-   ##
==========================================
- Coverage   90.51%   89.81%   -0.71%     
==========================================
  Files           7        7              
  Lines         622      638      +16     
==========================================
+ Hits          563      573      +10     
- Misses         59       65       +6

Impacted Files	Coverage Δ
immutablecollections/_immutabledict.py	84.21% <100%> (ø)	:arrow_up:
immutablecollections/_immutablemultidict.py	91.09% <84.21%> (-0.9%)	:arrow_down:
immutablecollections/_immutableset.py	89.86% <85.71%> (-1.14%)	:arrow_down:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update e7fe0bf...a6edb36. Read the comment docs.

[berquist]

Oh, forgot to say that I didn't touch ImmutableList. Should I bother?

[gabbard]

@berquist : don't bother with ImmutableList