switch to article search api v2

Since it seems like the index for v1 isn't updated anymore.

Docs at http://developer.nytimes.com/docs/read/article_search_api_v2

The resulting object has a different layout then what v1 returned, so
this should probably increase the major library version.
removed 5.3 build, added 5.5 build
Merge pull request #4 from rwos/topics/switch-to-articlesearch-v2

switch to article search api v2