Query parameters code example

We should have an example of query parameters in the CBL docs. References:

• http://docs.couchbase.com/mobile/2.0/couchbase-lite-net/db022/html/T_Couchbase_Lite_Query_Parameters.htm
• http://docs.couchbase.com/mobile/2.0/couchbase-lite-net/db022/html/M_Couchbase_Lite_Query_Expression_Parameter.htm