Removed sqlite3-unicodesn submodule
Don't store sequence in CBL_Revision on document put

This doesn't have any benefits yet, but will eventually let me make
puts asynchronous (since the sequence number is only known after the
put completes.)
On Mac, link against CBForest static lib, not framework

That way clients don't have to link the CBForest.framework too
Limited full-text search support

* Need to set the view's indexType to kCBLFullTextIndex.
* Query's fullTextSnippets and fullTextRanking are ignored.
* Query rows are normal CBLQueryRows, not FBLFullTextQueryRows.
* In a query row only the docID is meaningful.