Freed some more memory

SW_Main.c
	06/24/2013	(rjm)	included "SW_Site.h" and "SW_Weather.h";
						added calls at end of main() to SW_SIT_clear_layers() and
SW_WTH_clear_runavg_list() to free memory
SW_Weather.c
	06/24/2013	(rjm) added function void SW_WTH_clear_runavg_list(void) to
free memory
SW_Site.c
	06/24/2013	(rjm) added function void SW_SIT_clear_layers(void) to free
allocated soil layers