Replace coveralls with codecov.io

[pavdmyt]

No description provided.

[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (master@6db90ca). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #83   +/-   ##
=========================================
  Coverage          ?   95.11%           
=========================================
  Files             ?        6           
  Lines             ?      307           
  Branches          ?        0           
=========================================
  Hits              ?      292           
  Misses            ?       15           
  Partials          ?        0           

---

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 6db90ca...c8b3324. Read the comment docs.