missing maux and dimension statement
tstart var in conck should have been changed when variable replaced by either tstart_thisrun or t0
added dimension statement for aux - safer this way
changed name of unused variable dtv2 -> dt_max. Add line to use it in tick - default in setrunn is 1e98 so shouldn't change anything unless actually set it in setrun.py:
changed to use dt_max in setrun.py to avoid huge cfl numbers when vt=0
Merge pull request #73 from mjberger/master

missing maux and dimension statement, also adds some name changes.