AngelScript: math functions

# math functions

Path: /sdk/add_on/scriptmath/

This add-on registers the math functions from the standard C runtime library with the script engine. Use `RegisterScriptMath(asIScriptEngine*)` to perform the registration.

By defining the preprocessor word AS_USE_FLOAT=0, the functions will be registered to take and return doubles instead of floats.

## Public script interface

      float cos(float rad);
      float sin(float rad);
      float tan(float rad);
      float acos(float val);
      float asin(float val);
      float atan(float val);
      float atan2(float y, float x);
      float cosh(float rad);
      float sinh(float rad);
      float tanh(float rad);
      float log(float val);
      float log10(float val);
      float pow(float val, float exp);
      float sqrt(float val);
      float ceil(float val);
      float abs(float val);
      float floor(float val);
      float fraction(float val);