Merge pull request #7 from tuncer/rebar-deprecation

Fix rebar deprecation warnings

rebar.config

@@ -1,6 +1,6 @@
 {port_sources, ["c_src/*.c"]}.
 {so_name, "skerl_nifs.so"}.
-{erl_opts, [debug_info, fail_on_warning]}.
+{erl_opts, [warnings_as_errors]}.
 {port_envs, [
              %% Make sure to link -lstdc++ on linux or solaris
              {"(linux|solaris)", "LDFLAGS", "$LDFLAGS -lstdc++"},