Merge branch 'modernize-raviart-thomas-elements' into 'master'
Modernize the Raviart-Thomas implementation a bit
See merge request !74 (merged)
(cherry picked from commit 72699092)
9dea9719 Test the RT0Cube2DLocalFiniteElement class 39634be9 Fix a bug in RT0Cube2DLocalInterpolation 07d7e196 Fix various bugs in RT02DLocalFiniteElement