added ErrorAccumulator to aid in calculating RMSE
converted piecewiseapprox.cpp and polyapprox.cpp to use new pure virtual method name and ErrorAccumulator
initial default range tweaked way down
rename "POP" template parameter to "POPSIZE"
added RunOneGeneration() method - generations can now be run one at a time
added SetRange(i,min,max) method
added a decent amount of comments through main algorithm and class declaration