Squashed 'subtree/quarks/' changes from 0dbd256..ed4ba32

ed4ba32 Added datetime extensions
ee127cd Require made internal
b066d09 Fixed enum indexer for non-int based enums
4e9681c Added tests for precise timer, allow to run repeater intervals
182f20b Added get values method to enum indexer
0b61d72 Added contracts
83ef1f8 Added thread extensions class

git-subtree-dir: subtree/quarks
git-subtree-split: ed4ba32a0f89c45ba13015c0d9da551a86c7f6c5
Merge commit '69eb31e3b1cf0a0034375c4d3469710d02b3c0f2'
Added enumerate files recursive method in folder class
Allow to set relative path to file overrides (close #24)