add old zero terms back in
Merge branch 'master' into derivative
Merge branch 'master' into derivative
Merge branch 'sort_terms' into derivative
Merge pull request #8 from stepthom/sort_terms

Sort terms
Merge pull request #9 from stepthom/derivative

Derivative
Merge branch 'master' into fractions

Conflicts:
	src/com/swtanalytics/math/MathFunction.java