Thousands

Added text about image diff example

Merge branches 'feature_division_polished' and 'feature_subtraction_polished'

Removing subtraction from the division line of code

Added subtract feature

Added call and import for subtraction

Used static imports to simpify the math calls

Removed unused Square class import

Added sum function and test call

Added shell script to drive the execution of the app

Ignored *.class files

Refactored squaring into a separate class

Added sqaring method

Addition of the README and basic Groovy source samples.