MATH-1175

"LaplaceDistribution": Fixed special case of inverse cumulative distribution.
MATH-1173: Tricubic interpolation

New class "TricubicInterpolatingFunction" to replace "TricubicSplineInterpolatingFunction".
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/commons-math

Conflicts:
	src/changes/changes.xml