Added much functionality to ksDensity

ksDensity function now works for double, float, and int inputs. float
input uses RenderScript kernels to vastly speed up computation time.
'run file' button in main menu was used to create a sample input for
double and float ksDensity functions, and it was crudely timed (just
System.currentTimeMillis() is good enough for this). Both outputs were
compared after running, and they are accurate element by element with a
tolerance of 5%. This is a high tolerance, but I'll look into tighter
accuracy later...

Although beware,: I noticed that there is some sort of C++ memory leak
somewhere in the ksDensity function....