Use provided memoize function for selectors

[srolel]

In addition to memoizedResultFunc.

[coveralls]

Coverage remained the same at 100.0% when pulling f0c8af4 on Mosho1:patch-1 into 92d16de on reactjs:master.

[codecov-io]

Codecov Report

Merging #297 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #297   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           1      1           
  Lines          15     15           
=====================================
  Hits           15     15

Impacted Files	Coverage Δ
src/index.js	100% <ø> (ø)	⬆️

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[skortchmark9]

@ellbee could you take a look at this? It would be really handy to have in

[ellbee]

Ok, this looks good to me. Will be released in version 4. Thanks!