build: Update jscs and use new "wikimedia" preset

Our coding style has been upstreamed as of
grunt-jscs-checker v0.6.0 (node-jscs v1.5.0).

Some rules were not previously enabled here.

* Disable validateIndentation due to upstream bug
  https://github.com/mdevils/node-jscs/issues/459
  (the weird switch cases we have in unicodejs.wordbreak.js trip
  the parser).

* Disable disallowQuotedKeysInObjects and requireSpacesInsideArrayBrackets
  for now (we can do that later, too many affected LOC).

* Fix missing space after comma (requireSpaceAfterBinaryOperators
  was previously missing ',' and '=').

Change-Id: Icb5b5415a2dd34172680d45c5a6b8cbf15189a4c