Adjust install paths and add LICENSE to installed files.

--- Makefile	2014-02-10 10:36:26.000000000 +0100
+++ Makefile	2015-10-23 20:24:01.308136083 +0200
@@ -26,7 +26,8 @@
 
 install: all
 	install -D -m755 ptii $(DESTDIR)$(PREFIX)/bin/ptii
-	install -D -m644 README $(DESTDIR)$(PREFIX)/share/doc/README
+	install -D -m644 README $(DESTDIR)$(PREFIX)/share/doc/ptii/README
+	install -D -m644 LICENSE $(DESTDIR)$(PREFIX)/share/licenses/ptii/LICENSE
 
 uninstall:
-	rm $(DESTDIR)$(PREFIX)/{bin/ptii,/share/doc/README}
+	rm $(DESTDIR)$(PREFIX)/{bin/ptii,/share/doc/ptii/README,/share/licenses/ptii/LICENSE}
