(#136) - Skip attachments tests which fail due to CouchDB 2.0 bugs

Skip attachment tests which fail due to missing support for attachments=true
in the CouchDB 2.0 changes feed
(https://issues.apache.org/jira/browse/COUCHDB-2519)
(#3214) - Remove chrome + webSQL configuration from travis
(#3219) - Updated losing revision in guide

To get a losing revision of a document, we have to use one out of the _conflicts-array.
(#3188) - fall back from JSON to vuvuzela
(#3211) - perf: remove unused metadata.seq idb index
(#3215) - update compaction docs
(#3222) - Fixed FAQ link URL
(#3209) - Switch bail default back to true
(#3217) - remove query() from test.basics.js
(#3213) - perf: don't store id and rev (idb)

There's no need to store the _id and _rev if
we already have _doc_id_rev. For map/reduce especially,
this takes up a lot of unnecessary space.
(#136) - Skip all_docs.keys assertions which fail under CouchDB 2.0

CouchDB 2.0 breaks compatiblity around query parameter validation for _all_docs.
Skip the tests which assert this until the bugs are fixed. Jira ticket is
https://issues.apache.org/jira/browse/COUCHDB-2523
(#136) - Skip all_docs.key assertions which fail under CouchDB 2.0

CouchDB 2.0 breaks compatiblity around query parameter validation for _all_docs.
Skip the tests which assert this until the bugs are fixed. Jira ticket is
https://issues.apache.org/jira/browse/COUCHDB-2523
(#3070, #3171) - Improve consistency of error handling

When handling errors the message should always be a string and match
the one defined in errors.js, and reason should be the reason
given by CouchDB. Errors from validate_doc_update (forbidden and unauthorized)
should match errors.FORBIDDEN and errors.UNAUTHORIZED and their
reason property should be the value thrown

Provides a single error handling mechanism for both browser and node and
single and bulk doc operations.
As a result:
- new errors are always created so that a newer errors do not override
 properties of previous errors (in bulk docs operations).
- errors contain information about which docs failed (their ID) and the reason
 of the failure. Particularly helpful in replication errors.
- error.message is the 'message' specified in errors.js and error.reason
 is the 'reason' given by the response.
(#3228) - refactor idb
(#3179) - Add test
(#3179) - Ensure documents are reported as deleted