Merge branch 'release/1.3.1'

Author: Alexander Perechnev

ChessKit.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |spec|
   spec.name         = "ChessKit"
-  spec.version      = "1.2.17"
+  spec.version      = "1.3.1"
   spec.summary      = "Lightweight and fast chess framework written in Swift."
 
   spec.description  = "Lightweight and fast chess framework written in Swift. ChessKit is used as a base freamework for Ladoga chess engine."