Optimization

Francisco,

Can I fit some more optimizations in before beta?  :)

The main benefit of this PR is that it eliminates unneeded arbitrary string value escaping.  This is particularly nice with bytea encoding, as the entire encoding operation, including quoting, is done in one scan, eliminating at least one potentially large copy operation.  It also eliminates arbitrary escape scans on all types other than raw text (no need to escape a Timestamp value, for example).  With arrays, the extra quoting and escaping operation that was being done in ArrayHandling.cs is now eliminated.

-Glen