ofConstants: Remove preprocessor constants and macros

These are definetely evil:

#ifndef PI
    #define PI       3.14159265358979323846
#endif

#ifndef TWO_PI
    #define TWO_PI   6.28318530717958647693
#endif

#ifndef M_TWO_PI
    #define M_TWO_PI   6.28318530717958647693
#endif

#ifndef FOUR_PI
    #define FOUR_PI 12.56637061435917295385
#endif

#ifndef HALF_PI
    #define HALF_PI  1.57079632679489661923
#endif

#ifndef DEG_TO_RAD
    #define DEG_TO_RAD (PI/180.0)
#endif

#ifndef RAD_TO_DEG
    #define RAD_TO_DEG (180.0/PI)
#endif

#ifndef MIN
    #define MIN(x,y) (((x) < (y)) ? (x) : (y))
#endif

#ifndef MAX
    #define MAX(x,y) (((x) > (y)) ? (x) : (y))
#endif

#ifndef CLAMP
    #define CLAMP(val,min,max) ((val) < (min) ? (min) : ((val > max) ? (max) : (val)))
#endif

#ifndef ABS
    #define ABS(x) (((x) < 0) ? -(x) : (x))
#endif

Suggestions

• PI
  • I suggest a constexpr value with M_PI.
• TWO_PI
  • Trivial change.
• M_TWO_PI
  • Trivial change.
• FOUR_PI
  • Trivial change.
• HALF_PI
  • Trivial change.
• DEG_TO_RAD
  • This should be a constexpr function.
• RAD_TO_DEG
  • This should be a constexpr function.
• MIN
  • This should use std::min().
• MAX
  • This should use std::max().
• CLAMP
  • This should be a constexpr function.
• ABS
  • This should use std::abs.
  • We need a float version which uses std::fabs too.