Bracket type parsing problem fixed (#52)

* Bracket type parsing problem fixed

* Bracket variable test added

Author: SinanMtl

graphql.js

@@ -252,7 +252,11 @@
       var types = []
       for (var key in variables) {
         var value = variables[key]
-        var keyAndType = key.split("!")
+        var keyAndType = key.split(/^(.*?)\!/)
+        if (keyAndType.length > 1) {
+          keyAndType = keyAndType.slice(1)
+          keyAndType[1] = keyAndType[1].replace(/(.*?)\!$/, "$1")
+        }
         var mapping = typeMap[typeof(value)]
         var mappedType = typeof(mapping) === "function" ? mapping(value) : mapping
         if (!key.match("!") && keyAndType[0].match(/_?id/i)) {