Master Mind solver

Minor EMCO fix

There was an issue with saving the timestamp constraint. This resolves it.

Master Mind Solver

This adds a new module, mastermindsolver, which you can use to solve Master Mind puzzles.

What is Master Mind?

Master Mind is a code-breaking game where a secret code is set and you attempt to figure out what it is.
The board game version is typically six different colors of peg which make up the code, and four code positions.
The solver makes a guess at the code, and is told how many items have the right color in the right position, and how many items are the right color, but in the wrong position.
This is most often represented with fully right guesses being colored pegs, and right color but wrong position being white pegs.
The solver then uses this information and any information from previous answers to make another guess.

A more thorough write up can be found on wikipedia

See the MasterMindSolver wiki for more info on using it.