Create GreenCrudPopulation.java

This program calculates green crud population numbers over a number of
 *  days. The user inputs the number of days and the starting population in
 *  pounds. The program assumes no deaths. The formula for the rate of growth 
 *  follows the Fibonacci number sequence. It also assumes 2 time periods to
 *  mature to reproducing age and then one reproduction per time period. This
 *  formula applies most directly toward asexual reproduction at a rate of one
 *  offspring per time period.