Add a Math static class for well known formulas

[irperez]

Here is a good example of physics formulas.

http://faculty.trinityvalleyschool.org/hoseltom/handouts/Formula%20Sheet-2003-05-07-8pg.pdf

Body Mass Index (BMI) => http://en.wikipedia.org/wiki/Body_mass_index
Body Surface Area (BSA) => http://www.halls.md/body-surface-area/refs.htm