Provide trigonometry functions

[zoubata]

Hi,
This is a very interesting lib for smal CPU without FPU.
On my case I need sin(x) cos(x),
It could be nice to add this into your library, with precomputed table.

[Pharap]

I will look into this in the future, but at the moment trigonometric functions haven't been provided simply because of the difficulty of providing functions that are both generic and efficient.

I have in the past written sine and cosine functions that accepted 'brads' ('binary radians' - where the values 0 to 256 map to degrees of 0 to 360), but I would need to research alternatives and performance costs before introducing anything into the library itself.