Update dependency to System.Data.SQLite Core

The latest version of System.Data.SQLite depends on System.Data.SQLite.Linq & System.Data.SQLite.EF6.  The EF6 package in turn depends on EntityFramework.  Moving to Core drops all of these dependencies.  It does require a bump from 1.0.88 to 1.0.92 so I'm not sure how you feel about that.  I ran the tests for Win32, the only platform affected, and they passed.  I did have problems with the async stress test failing, but this also happened to me before making any edits.