Add Foldable.foldMapM and Reducible.reduceMapM

[peterneyens]

This adds

• Foldable.foldMapM which is similar to foldM but using a Monoid instance
• Reducible.reduceMapM which is similar to reduceLeftM but using a Semigroup instance.

[codecov-io]

Current coverage is 92.23% (diff: 100%)

Merging #1452 into master will increase coverage by 0.03%

@@             master      #1452   diff @@
==========================================
  Files           242        242          
  Lines          3615       3617     +2   
  Methods        3543       3551     +8   
  Messages          0          0          
  Branches         72         66     -6   
==========================================
+ Hits           3333       3336     +3   
+ Misses          282        281     -1   
  Partials          0          0          

Powered by Codecov. Last update 2fd55c5...9e755de

[codecov-io]

Current coverage is 92.23% (diff: 100%)

Merging #1452 into master will increase coverage by 0.03%

@@             master      #1452   diff @@
==========================================
  Files           242        242          
  Lines          3615       3617     +2   
  Methods        3543       3551     +8   
  Messages          0          0          
  Branches         72         66     -6   
==========================================
+ Hits           3333       3336     +3   
+ Misses          282        281     -1   
  Partials          0          0          

Powered by Codecov. Last update 2fd55c5...9e755de

[johnynek]

👍

[travisbrown]

👍, this looks great!