Fix Math collection operators
Fix detection of common value class from array
Fix Property declaring correct produced value class
Fix Transformer.formatString: crash, improve formatting different counts
Merge branch 'master' of https://github.com/iMartinKiss/Objective-Chain

# By Juraj Homola
# Via Juraj Homola
* 'master' of https://github.com/iMartinKiss/Objective-Chain:
  OCAFilter: Add produceNotNil filer
  OCATransformer+Collections: Fix misused "keys" and "key" variable in keyedArray: method.