Remove various JSHint-related cruft

We use ESLint now, which is smarter about some things.

lib/compiler/js.js

@@ -12,12 +12,13 @@ var js = {
      * may appear in the form of an escape sequence.
      *
      * For portability, we also escape all control and non-ASCII characters.
-     * Note that "\0" and "\v" escape sequences are not used because JSHint does
-     * not like the first and IE the second.
+     * Note that the "\v" escape sequence is not used because IE does not like
+     * it.
      */
     return s
       .replace(/\\/g,   '\\\\')   // backslash
       .replace(/"/g,    '\\"')    // closing double quote
+      .replace(/\0/g,   '\\0')    // null
       .replace(/\x08/g, '\\b')    // backspace
       .replace(/\t/g,   '\\t')    // horizontal tab
       .replace(/\n/g,   '\\n')    // line feed

spec/behavior/generated-parser-behavior.spec.js

@@ -71,7 +71,7 @@ describe("generated parser behavior", function() {
       toFailToParse: function(input, details, options) {
         options = options !== undefined ? options : {};
 
-        var result;
+        var result, key;
 
         try {
           result = this.actual.parse(input, options);
@@ -86,12 +86,6 @@ describe("generated parser behavior", function() {
 
           return false;
         } catch (e) {
-          /*
-           * Should be at the top level but then JSHint complains about bad for
-           * in variable.
-           */
-          var key;
-
           if (this.isNot) {
             this.message = function() {
               return "Expected " + jasmine.pp(input)

spec/unit/compiler/passes/helpers.js

@@ -61,7 +61,8 @@ beforeEach(function() {
     },
 
     toReportError: function(grammar, details) {
-      var ast = peg.parser.parse(grammar);
+      var ast = peg.parser.parse(grammar),
+          key;
 
       try {
         this.actual(ast);
@@ -75,12 +76,6 @@ beforeEach(function() {
 
         return false;
       } catch (e) {
-        /*
-         * Should be at the top level but then JSHint complains about bad for
-         * in variable.
-         */
-        var key;
-
         if (this.isNot) {
           this.message = function() {
             return "Expected the pass not to report an error "

spec/unit/parser.spec.js

@@ -204,7 +204,7 @@ describe("PEG.js grammar parser", function() {
       },
 
       toFailToParse: function(details) {
-        var result;
+        var result, key;
 
         try {
           result = peg.parser.parse(this.actual);
@@ -219,12 +219,6 @@ describe("PEG.js grammar parser", function() {
 
           return false;
         } catch (e) {
-          /*
-           * Should be at the top level but then JSHint complains about bad for
-           * in variable.
-           */
-          var key;
-
           if (this.isNot) {
             this.message = function() {
               return "Expected " + jasmine.pp(this.actual) + " to parse, "