Added a preliminary draft for a Makefile facilitating various jobs

Makefile

+flowspytag = $(shell git describe --abbrev=0)
+flowspyver = $(shell git describe --abbrev=0 | egrep -o '([0-9]\.){1,10}[0-9]')
+
+.PHONY: dist distclean
+
+dist: 
+	git archive --format tar --prefix flowspy-$(flowspyver)/ -o flowspy-$(flowspyver).tar $(flowspytag)
+	gzip -f flowspy-$(flowspyver).tar
+distclean:
+	@rm -f *tar.gz
+