The heating rate should be a scalar function.
Update minimum refinement function to always read in 3 variables.
Merge pull request #176 from bangerth/fix-default-function

The heating rate should be a scalar function.
Merge pull request #177 from gassmoeller/split_refinement_functions

Workaround for some not working parameter files.
Use strain rate for viscosity mesh refinement.
Merge pull request #178 from gassmoeller/fix_viscosity_refinement

Use strain rate for viscosity mesh refinement.
Implemented new pressure compatibility correction.
Addressed comments.
Merge pull request #131 from gassmoeller/compatibility_normal_flux

Compatibility normal flux
Merge remote-tracking branch 'geodynamics/master'
Incorporated bugfix from minimum refinement function to standardize the way variables are read for different coordinate systems.
Merge branch 'fix_max_refinement'
Fixed indexing bug.
Merge pull request #180 from jperryhouts/fix_max_refinement

Incorporated bugfix from minimum refinement function to standardize the way variables are read for different coordinate systems.
Merge remote-tracking branch 'geodynamics/master'
Updated comments for Doxygen formatting.