Move spawning to start function.
Small refactor.
Fixed type specs.
Update travis tests.
Test simplifiaction and fixup.
Initial logic for map-pull workers.
Fix place in which pid sources are created.
Fix partitioning and combining data.
Dirty test fix.
Use both API for map (pull an push).
Split different workers handling in three modules.

Still some work to do ...
Fix some of `Elvis` clean code comments.
Code clenup.
Merge pull request #5 from ParaPhraseAGH/map_pull

Map with work stealing