Adjust bulk copier interface to be saner

Issue #37
Issue #38
Add sql-ops :over, :partition-by, :with, :with-recursive, and :window

Plus slight additions to the exits sql-ops :order-by and :select.
Remove duplicate definition of s-sql op @>
Fix syncing after send-copy-done receives an error response

Deal with the fact that sending a COPY as a simple query causes an implicit
sync to happen after the copying.

Issue #39
[S-SQL] Add support for adding and dropping columns and adding named constraints to ALTER-TABLE

Keep the :ADD option for backwards-compatibility
[S-SQL] Add documentation on the new features of ALTER-TABLE
Add double-float clause to cl-postgres:to-sql-string
typo: *table-name*->*table-symbol*

The documentation of *table-symbol* was being set to *table-name*
Don't try to define a double-float method on CLISP

It apparently does not support that.
Merge remote-tracking branch 'marijnh/master'

Conflicts:
	cl-postgres/bulk-copy.lisp