Created functional subpackage, added Function1 and Function2
Added Mapping
Added javadoc to Mapping.java + fixed a minor bug
Modified .gitignore, added AMath.java, PolynomialFunction.java, LinearFunction.java
Small change to Function2.java
Merge branch 'master' into math_statistics

Needed stuff from functional that didn't exist when branch was
created (I suck at git, I know...)
Merge branch 'math_general' into math_statistics

Merge in AMath
Added ExponentialDistribution.java