Add trigonometric functions to `math.r2py`

[aaaaalbert]

We should have basic trigonometric functions like sin, cos, and tan in Repy too. The implementation should be based on math_e, the exponentiation operator **, and complex value operations.

https://en.wikipedia.org/wiki/Euler's_formula has the math.

[kellender]

I made a PR for trig functions: #181
I forgot to ask you about how many decimal place you wanted.