making NaN now bright green
iterating now correctly through rectangle-task
added utility class for computing histograms of floats
more stuff to prevent NaN

0/0 is bad,
sqrt of negative number is bad
some minor changes of project settings

using java 8? most likely a bad idea <.<
added correct box car image
added double sided diffuse material for path tracing scenes

fixes visor etc.
readded inv function, only used in tests so far

will possibly remove this at some point