(#1848) - housekeeping on query() docs

Adds more notes to the db.query()
documentation, especially when we
forgot to mention certain
parameters. Also adds documentation for
options.stale and options.group_level.

The only new code this will require in
order to be accurate is pouchdb/mapreduce#85.
(#1860) - Fix info.doc_count for websql/idb
(#1869) - performance improvements for idb.get

Also includes some generic performance
improvements for merge.traverseRevTree and
utils.isDeleted.
(#1873) - Split out argsarray into its own module
(#1875) - use a library for extend, and then use clone for the 95% of the time where that is what we are using extend for
(#1753) - remove es5 shims
(#1826) - fix level alt going forward
(#1826) - fix level alt going forward
(#1826) - Reremove es5 shim + extend from alt branch
(#1871) - WebSQL total_rows/get performance boosts
(#1887) - Don't leak PouchDB.utils in docs
(#1885) - Only run travis on master + pull requests
(#1734) - leveldb simultaneus write race condtions
(#1734) - leveldb doc writing race conditions