Add an explicit test of BLOB type.
TODO that should have been done at the same time.
Make sure use VAR types as widest.
Now fix the tests that were still inserting into a BLOB with a string without conversion.
merge MMcM: Make BLOB encoding binary and fix fallout from that

Merge pull request #1147 from MMcM/sql-layer/blob-encoding
https://github.com/FoundationDB/sql-layer/pull/1147