Move mg_task to SimpleLink platform code

It'll be used for MSP432 as well

PUBLISHED_FROM=cb5dcda4cc5d9edc6dea71540d51ab00e252186e

examples/CC3200/Makefile

@@ -7,6 +7,9 @@ PORT ?= auto
 MAKEFLAGS += w
 
 all clean:
+	rm -rf ccs/*/Debug
+	rm -rf ccs/*/Release
+	rm -rf ccs/*/.launches
 	docker run --rm -i -v $(SRC_DIR):/src $(SDK) \
 		/bin/bash -c "\
 			make -C /src/mongoose mongoose.c mongoose.h && \