Made CBLWebSocketChangeTracker work correctly with CBLAuthorizer

Also found that it didn't work correctly if usePOST property wasn't set,
so I fixed that too.
Fixes #400
Skip FMDB thread-safety check when running on dispatch queues.

Fixes #376
Better handling of a model's document being deleted

* Clear all properties
* Clear needsSave flag, remove from db's docs-to-be-saved set
* Detach from document even if the model didn't initiate the save
* Don't call didLoadFromDocument
Fixes #363
Enable JS filter compiler support

The function CBLRegisterJSViewCompiler() now also registers the JS
filter compiler.
Also, enabled JS filters in LiteServ.
Oops, actually enable JS filters in LiteServ
Allow logging to be redirected, and use NSLog on iOS devices

* Added +[CBLManager redirectLogging:]
* On iOS devices, always log to NSLog, since stderr output doesn't get
  saved anywhere that can be viewed later.
Fixes #395
Add JSONObjectWithDate:timeZone: to get a date with tz-offset.
Add Tests for +JSONObjectWithDate:timeZone.
Added more auth-failure error codes to CBLIsPermanentError

See https://groups.google.com/d/msgid/mobile-couchbase/35f2db0b-bd47-4579-9afa-23f92745eeb0%40googlegroups.com
Merge pull request #401 from monowerker/topic/date_w_tz

Add time zone support to CBLJSON date formatter