STYLE: Changes the name of math constants

Changes the name of math constants to be consistent

Base/Core/imstkMath.h

@@ -74,7 +74,7 @@ const double PI_2 = 1.57079632679489661923;
 const double PI_4 = 0.785398163397448309616;
 const double INV_1_PI = 0.318309886183790671538;
 const double INV_2_PI = 0.636619772367581343076;
-const double _2_SQRTPI = 1.12837916709551257390;
+const double TWO_OVER_SQRTPI = 1.12837916709551257390;
 const double SQRT2 = 1.41421356237309504880;
 const double SQRT1_2 = 0.707106781186547524401;
 const double NLOG_E = 2.71828182845904523536;