Implement CouchDB “connection_timeout” replication option

Value is desired timeout in milliseconds, e.g. 60000 for 1 minute.
This applies to all HTTP requests sent by the replicator.
Default is 1 minute.
Fixes couchbaselabs/touchdb-ios#270

Conflicts:
	Source/CBLRemoteRequest.h
	Source/CBLRemoteRequest.m
	Source/CBL_Replicator.m
More CouchDB conformance fixes

* On upload of doc with attachments, reject if stub attachment has a bogus “revpos”.
* DELETE of attachment with no revid given should return 409, not 404.
* “reduce” view option should default to true if view has a reduce function.
* _compact should return 202, not 206.