Fix a path-escaping bug with replication

Regression from the initial BrowserID patch (649d14f)
TDModel autosave delay is now extendable

Just override -autosaveDelay in your TDModel subclass.
(Default value is 0.0.)
Allow nonpersistent TDReplication to be started again if it stops

Also made the -stop method work.
Internal change notification improvements

Created a TD_DatabaseChange class to encapsulate info about a new
revision. Added a flag that indicates whether the document may be in
conflict (not used yet.)
Fixed regression where persistent TDReplication never notified

Persistent TDReplications were never posting progress-changed
notifications. Fixed now.
Fix crash in TDJSViewCompiler

The compiled function objects were getting GC'd, after which calling them would crash.