For thorns which need the stress energy tensor

Spacetime evolution thorns and various analysis thorns (e.g. one which computes the constraints) may need to know the value of the stress-energy tensor. See thorn CactusEinstein/ADM for an example the former. There the macro KSOURCES (see KSOURCES_declare.h and KSOURCES_guts.h) is called from the various time integration source files DoubleLeap.F, IterativeCN.F, etc., which in turn include the CalcTmunu_temps.inc and CalcTmunu.inc files. In this example, the $T_{\mu\nu}$ temporary variables are provided by including CactusEinstein/ADMMacros/src/macro/TRT_declare.h.