Intellisense: Evalute color variables's value

For implicit variable evaluation, this PR will tokenize and calculate the value of each channel separately. Then it consumes [ncalc](https://ncalc.codeplex.com/discussions/346702) to evaluate three (integer) expressions.

Perhaps, in future if they will entertain [this request](https://ncalc.codeplex.com/discussions/537956), we would be able to evaluate the entire triplet hexa expression (hexa color code; `#AABBCC`).