(#1238) - Minor fixes and additions to docs

Fixes some small spelling/grammar errors in the docs
and adds some more information, especially to the
API page.
(#1239) - Favor GETs over POSTs for Safari

The test "all_docs: http-1: Testing allDocs opts.keys" breaks
in Safari because Safari cannot comprehend why a POST
would return a 304.  This commit fixes that.

Currently we always turn a GET into
a POST if "keys" is provided. So my proposal is to only do this
if "keys" would make the URL longer than 2000 characters,
since CouchDB accepts both a GET and a POST.
(#1218) - bring in version
(#1244) - fix leveldb validity check so it will fail in the browser
(#1253) - Ensure we only start the tests once
(#1257) - Escape _id in bulkDocs for WebSQL

Before this fix, quotes in doc ids inserted using
bulkDocs would crash WebSQL, since we were just
wrapping quotes around the id string.

I also went ahead and ensured that the WebSQL
adapter properly reports SQLError objects, since
before it would only give an unhelpful 500 with
no message.
(#1245) Use tmp directory for test dbs and remove it afterwards.

Instead of the temporary databases being created in the repository base they are created in './tmp'
(#1276) - bulkDocs with empty doc list is now valid
(#1265) - remove test directory
(#1279) - clean up errors in websql
(#1283) - Add documentation re: attachment performance