Split julia and mandelbrot from imaginaryNumber class, what were they
doing there anyways? generally made ImaginaryNumber class more
standalone - added equals, tostring, hashCode and Pow methods. 

also added first beta version of a "generic set" which i hope will be a
set whose rules can be modified during runtime, basically TODO.
Currently broken : "pow2" in imaginaryNumber and "toShortString" in
imaginaryNumbers - /TODO