Comment 2 for bug 90809

I was going to do this as part of the pg 9 migration, but there is quite a bit of fallout. We will deal with standard_confirming_strings separately, so any fallout from pg 9 or standard_confirming_strings is correctly attributed.

There are two major areas I've seen where we expect plain quoted strings to accept backslash quoting:
 - regular expressions
 - accidental binary -> text casting. In particular, byte strings passed to Storm are sent as binary and at some point this is being reassembled to text. We should be passing Unicode, but we don't notice.