Move .app file to ebin; update Makefile.

Makefile

@@ -1,7 +1,5 @@
 all:
-	@test -d ebin || mkdir ebin
-	@cp src/oauth.app ebin/
 	@erl -make
 
 clean:
-	@rm -rf ebin/* erl_crash.dump
+	@rm -rf ebin/*.beam erl_crash.dump