fix a bug in reading $PERMEABILITY_FUNCTION_POROSITY
ConvergenceCheck should check only variables of corresponding process
extend norm calculation for some more data types
add TXNestedFunction
experimental support of dynamic porosity and porosity dependent permeability
take MMP at integration points
fix a bug in converge check
extend ReactGIAReduct to support porosity update
update example input files for porosity update
Merge pull request #23 from norihiro-w/add-porosity-update

Add porosity update