Makefile: improve performance detecting if a library is installed before compiling it again (in GNU/Linux and OSX). Centralize de tracking.log file. Improve the target install-python27 to be used when a GNU/Linux or OSX hasn't got python installed.
Makefile: improve performance detecting if a library is installed before compiling it again (in GNU/Linux and OSX). Centralize de tracking.log file. Improve the target install-python27 to be used when a GNU/Linux or OSX hasn't got python installed.

ahMarrone/solar_radiation_model,gersolar/solar_radiation_model,scottlittle/solar_radiation_model