Rename "grunt-jscs-checker" to "grunt-jscs"

Now grunt-jscs-checker's name is renamed to "grunt-jscs".
https://github.com/gustavohenke/grunt-jscs/commit/033b836742cc10c4a6d422a0b53e48604d5e92c1
Refine Amazon Extractors

* Amazon Extractor: Add support for more product page
* "Photo - Amazon" Extractor: Add support for more photo page
* Make context check strict