Update SqlServerStorage and Sample.MVC Sqlite usage

Update SqlServerStorage to only use one table - `MiniProfilers` in place of the old setup that includes multiple tables. The timing data is now serialized to JSON and stored in this table (which contains one row per page being profiled).

Also updated Sample.MVC to turn back on all functions that use Sqlite as the DB engine (had been turned off waiting for the update to SqlServerStorage).