Adds support for filtered push replication.

This commit adds support for filtered push replication via the CDTPushReplication
interface. A developer supplies the definition of the filter via a CDTFilterBlock,
and the query parameters via a NSDictionary.

* Adds CDTPushReplication -filter and -filterParams.
* Modifies CDTReplicationFactory -oneWay:error: to wrap the CDTFilterBlock
inside a TD_FilterBlock and into the source TD_Database so that TDPusher finds
the filter during replication.
* Adds tests in Tests project DatastoreCrud.m and CDTReplicationTests.m.
* Adds tests in ReplicationAcceptance project.
* Improves some documentation in CDTPullReplication and matches that in CDTPushReplication.
Yeah, you're right... 
All of these tests ReplicationAcceptance.m aren't very useful. They were more useful for my own sanity checks when I was writing the code. But they shouldn't be here. They are already in Tests/CDTReplicationTests.m so I'm removing them.