Merge pull request #99 from ericmj/patch-1

Support non rebar tools evaluating script

rebar.config.script

@@ -1,8 +1,11 @@
-{ok, VSN} = application:get_key(rebar, vsn),
+IsRebar3 = case application:get_key(rebar, vsn) of
+               {ok, VSN} ->
                    [VSN1 | _] = string:tokens(VSN, "-"),
                    [Maj, Min, Patch] = string:tokens(VSN1, "."),
-IsRebar3 = (list_to_integer(Maj) >= 3),
-
+                   (list_to_integer(Maj) >= 3);
+               undefined ->
+                   false
+           end,
 
 Rebar2Deps = [
               {cf, ".*", {git, "https://github.com/project-fifo/cf", {tag, "0.2.0"}}}