A simple, console-based, implementation of the game Mastermind

##Description Mastermind is a game where a player acts as a "code-breaker", trying to guess a secret code chosen by the computer. By default the code is 4 digits long, composed of the numbers 1 to 6, and the player will have 10 guesses to get it right.

After each guess, a series of + and - symbols will be displayed. Each - represents a correct number guessed, but in the wrong position. Each + represents a number guessed in the correct position.

##Settings The default settings can be overridden by providing several optional arguments when launching the game:

Arg  -   Type    -   Description
0    -   boolean -   Sets whether duplicate values should be allowed in the secret code
1    -   int     -   Sets number of guesses give to the user
2    -   int     -   Sets the length of the generated secret code
3    -   int     -   Sets the lower bound (inclusive) for each code value (0-9)
4    -   int     -   Sets the upper bound (inclusive) for each code value (0-9)