Remove usage of lodash _.assing and _.forOwn.

Relates to #68.

src/lang/lang_extensions.ts

@@ -49,7 +49,7 @@ namespace chevrotain.lang {
         }
 
         putAll(other:HashTable<V>):void {
-            this._state = _.assign(this._state, other._state)
+            this._state = utils.assign(this._state, other._state)
         }
 
         get(key:string):V {

src/scan/tokens_public.ts

@@ -43,9 +43,7 @@ namespace chevrotain {
         }
 
         // static properties mixing
-        _.forOwn(parentConstructor, (v, k) => {
-            derivedCostructor[k] = v
-        })
+        derivedCostructor = utils.assign(derivedCostructor, parentConstructor)
 
         // the tokenName property will be used by the Parser for Error Messages if the Token's constructor is anonymous
         derivedCostructor.tokenName = tokenName

src/utils/utils.ts

@@ -252,4 +252,19 @@ namespace chevrotain.utils {
         }
         return result
     }
+
+    /**
+     * mutates! (and returns) target
+     */
+    export function assign(target:Object, ...sources:Object[]):Object {
+        for (let i = 0; i < sources.length; i++) {
+            let curSource = sources[i]
+            let currSourceKeys = keys(curSource)
+            for (let j = 0; j < currSourceKeys.length; j++) {
+                let currKey = currSourceKeys[j]
+                target[currKey] = curSource[currKey]
+            }
+        }
+        return target
+    }
 }

test/utils/utils_spec.ts

@@ -173,5 +173,11 @@ namespace chevrotain.utils.spec {
             expect(() => zipObject(["ima", "aba"], [1, 2, 3])).to.throw("can't zipObject")
             expect(zipObject([], [])).to.deep.equal({})
         })
+
+        it("exports an assign utility", () => {
+            expect(assign(["ima", "aba", "bamba"], [1, 2, 3])).to.deep.equal([1, 2, 3])
+            expect(assign({}, {"ima": 666}, {"aba": 333})).to.deep.equal({"ima": 666, "aba": 333})
+            expect(assign({}, {"ima": 666}, {"aba": 333}, {"ima": 999})).to.deep.equal({"ima": 999, "aba": 333})
+        })
     })
 }