Re: Transparent column encryption

Here is an updated patch.  I have done some cosmetic polishing and fixed 
a minor Windows-related bug.

In my mind, the patch is complete.

If someone wants to do some in-depth code review, I suggest focusing on 
the following files:

* src/backend/access/common/printtup.c
* src/backend/commands/colenccmds.c
* src/backend/commands/tablecmds.c
* src/backend/parser/parse_param.c
* src/interfaces/libpq/fe-exec.c
* src/interfaces/libpq/fe-protocol3.c
* src/interfaces/libpq/libpq-fe.h

(Most other files are DDL boilerplate or otherwise not too interesting.)