Makefile: fixes #4. Add variable POSTGRES_PATH, gives some time after initdb and pg_ctl start, redirect error to tracking.log, and improve pg-stop and clean targets.
Makefile: fixes #4. Add variable POSTGRES_PATH, gives some time after initdb and pg_ctl start, redirect error to tracking.log, and improve pg-stop and clean targets.

gersolar/solar_radiation_model,ahMarrone/solar_radiation_model,scottlittle/solar_radiation_model