Make JSHint config compatible with JSHint v2.8.x and v2.9.x

 - Use the legacy 'esnext' option only instead of both
   'esnext' and 'esversion' for compatibility with JSHint v2.8.x
   on Hound and developers who have the current stable version
   installed locally.

 - Remove the 'maxErrors' option from the JSCS config, as this
   prevents use of the '-x' option to autofix files which is
   a little annoying.

.jscsrc

@@ -11,7 +11,6 @@
     "h/static/styles/vendor/**",
     "node_modules/**"
   ],
-  "maxErrors": 10,
   "disallowSpacesInAnonymousFunctionExpression": null,
   "disallowSpacesInFunctionDeclaration": {
     "beforeOpeningRoundBrace": true

.jshintrc

@@ -9,7 +9,6 @@
   "strict": "global",
   "undef": true,
   "unused": true,
-  "esversion": 6,
   "esnext": true,
   "globals": {
     "chrome": false,