fix small issue with refinement matrix for istret=3

Update CMake to include Cavity case

Use explicit formatting strings for XDMF writer

Experimental support for 2D simulations

Merge pull request #134 from pbartholomew08/76-new-code-maintains-single-restart-file-but-prints-multiple-restartinfo-files

76 new code maintains single restart file but prints multiple restartinfo files

Merge branch 'master' into 76-new-code-maintains-single-restart-file-but-prints-multiple-restartinfo-files

Use arbitrary length integers to timestamp snapshots

Use implicit none in variables.f90

maxval debug

Compare reference tgv output

Update reference output TGV data