fix(chessboard): make computer respond on move 1

[willb335]

@furrykef

• Shows 'not-allowed' cursor for no-drag pieces
• Addresses problem shown in PrestoChango demo

Take a look at Demo.js with PrestoChango added

I also tested the changes by playing the Stockfish engine and the moves are being played out in the correct order as far as I can tell

[codecov-io]

Codecov Report

Merging #32 into master will increase coverage by 0.13%. The diff coverage is 50%.

@@            Coverage Diff             @@
##           master      #32      +/-   ##
==========================================
+ Coverage   62.73%   62.86%   +0.13%     
==========================================
  Files          10       10              
  Lines         271      272       +1     
  Branches       62       62              
==========================================
+ Hits          170      171       +1     
  Misses         80       80              
  Partials       21       21

[willb335]

closed with https://github.com/willb335/chessboardjsx/commit/0b2884ccb9ab0514fd887efe064ab3d17770c9f2