Make sure merl gets built when using rebar (#123)

Makefile

@@ -4,20 +4,18 @@ REBAR=./rebar $(REBAR_ARGS)
 
 all: compile
 
-compile: check-slex deps/merl
+compile: check-slex get-deps
 	@$(REBAR) compile
 
 check-slex: src/erlydtl_scanner.erl
 src/erlydtl_scanner.erl: src/erlydtl_scanner.slex
 	@echo Notice: $@ is outdated by $<, consider running "'make slex'".
 
-deps/merl:
+get-deps:
 	@$(REBAR) get-deps
-	@echo "Make merl..." ; $(MAKE) -C deps/merl
 
-update:
+update-deps:
 	@$(REBAR) update-deps
-	@echo "Make merl..." ; $(MAKE) -C deps/merl
 
 compile_test:
 	-mkdir -p ebintest

rebar.config

@@ -7,3 +7,5 @@
    {git, "git://github.com/erlydtl/merl.git", {branch, "erlydtl"}},
    [raw]}
  ]}.
+
+{pre_hooks, [{compile, "make -C $REBAR_DEPS_DIR/merl all"}]}.