Finally converted CBLQueryOptions from a struct to an Obj-C class.

Cherry-picked from forestdb branch.

Conflicts:
	Source/API/CBLQuery.m
	Source/CBLDatabase+Internal.h
	Source/CBLDatabase+Internal.m
	Source/CBLView+Internal.h
	Source/CBLView+Querying.m
	Source/CBL_Database_Tests.m
	Source/CBL_Router+Handlers.m
	Source/CBL_View_Tests.m
	vendor/CBForest
Back-ported CBJSONEncoder from the forestdb branch

This replaces CBLCanonicalJSON. It's a faster encoder that uses the C
yajl library.
Unit tests for CBJSONEncoder

Also added some improvements to handling of booleans vs. small integers.