Detect newlines using charCodeAt instead of charCode

In generated parsers, detect newlines using charCodeAt instead of
charCode. This should be slightly faster.

lib/compiler/passes/generate-js.js

@@ -1001,7 +1001,7 @@ function generateJS(ast, options) {
     '        };',
     '',
     '        while (p < pos) {',
-    '          if (input.charAt(p) === "\\n") {',
+    '          if (input.charCodeAt(p) === 10) {',
     '            details.line++;',
     '            details.column = 1;',
     '          } else {',

lib/parser.js

@@ -439,7 +439,7 @@ module.exports = (function() {
         };
 
         while (p < pos) {
-          if (input.charAt(p) === "\n") {
+          if (input.charCodeAt(p) === 10) {
             details.line++;
             details.column = 1;
           } else {