Improve performance of all feature calculations

[kmax12]

Feature calculation makes several calls to Entity.query_by_values. This pull request optimizes these calls using a pandas merge instead of isin.

This is still a work in progress as we benchmark it across different datasets.

[codecov-io]

Codecov Report

Merging #224 into master will decrease coverage by 0.02%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #224      +/-   ##
==========================================
- Coverage   93.64%   93.62%   -0.03%     
==========================================
  Files          71       71              
  Lines        7679     7654      -25     
==========================================
- Hits         7191     7166      -25     
  Misses        488      488

Impacted Files	Coverage Δ
featuretools/tests/entityset_tests/test_es.py	99.34% <ø> (-0.01%)	⬇️
...utational_backend/test_calculate_feature_matrix.py	99.27% <ø> (-0.02%)	⬇️
featuretools/entityset/entityset.py	93.59% <ø> (-0.16%)	⬇️
featuretools/entityset/entity.py	89.71% <100%> (+0.17%)	⬆️

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