Add more dialyzer warnings to rebar.config.

rebar.config

@@ -1,2 +1,8 @@
-{dialyzer_opts, [src]}.
+{dialyzer_opts, [src, {warnings, [
+	behaviours,
+	error_handling,
+	race_conditions,
+	unmatched_returns
+%%	underspecs
+]}]}.
 {erl_opts, [bin_opt_info, warnings_as_errors, warn_export_all]}.