Remove usage of lodash _.zipObject.

Relates to #68.

src/scan/lexer.ts

@@ -25,7 +25,7 @@ namespace chevrotain {
             return addStartOfInput(currClass[PATTERN])
         })
 
-        let allPatternsToClass = _.zipObject(<any>allTransformedPatterns, onlyRelevantClasses)
+        let allPatternsToClass = utils.zipObject(<any>allTransformedPatterns, onlyRelevantClasses)
 
         let patternIdxToClass:any = utils.map(allTransformedPatterns, (pattern) => {
             return allPatternsToClass[pattern.toString()]

src/utils/utils.ts

@@ -240,4 +240,16 @@ namespace chevrotain.utils {
         result.sort((a, b) => orderFunc(a) - orderFunc(b))
         return result
     }
+
+    export function zipObject(keys:any[], values:any[]):Object {
+        if (keys.length !== values.length) {
+            throw Error("can't zipObject with different number of keys and values!")
+        }
+
+        let result = {}
+        for (let i = 0; i < keys.length; i++) {
+            result[keys[i]] = values[i]
+        }
+        return result
+    }
 }

test/utils/utils_spec.ts

@@ -166,7 +166,12 @@ namespace chevrotain.utils.spec {
         it("exports a sortBy utility", () => {
             expect(sortBy([1, 2, 3], (num) => num)).to.deep.equal([1, 2, 3])
             expect(sortBy([3, 2, 1], (num) => num)).to.deep.equal([1, 2, 3])
+        })
 
+        it("exports a zipObject utility", () => {
+            expect(zipObject(["ima", "aba", "bamba"], [1, 2, 3])).to.deep.equal({"ima": 1, "aba": 2, "bamba": 3})
+            expect(() => zipObject(["ima", "aba"], [1, 2, 3])).to.throw("can't zipObject")
+            expect(zipObject([], [])).to.deep.equal({})
         })
     })
 }