/// Returns 'base' raised to the power 'exponent'.
///
/// @param x pow function is defined for input values of x defined in the range (inf-, inf+) in the limit of the type precision.
/// @param y
/// @param base Floating point value. pow function is defined for input values of x defined in the range (inf-, inf+) in the limit of the type precision.
/// @param exponent Floating point value representing the 'exponent'.
/// @tparam genType Floating-point scalar or vector types.
///
/// @see <a href="http://www.opengl.org/sdk/docs/manglsl/xhtml/pow.xml">GLSL pow man page</a>