New column page

Shows SQL for columns ALTER TABLE ... [ADD|DROP] COLUMN combines a selection
of multiple columns into a single alter table.
Show collation in list of columns.

(order of columns isn't what is should be but that should maybe be fixed
by a generic column selection and ordering mechanism that knows what the
default sort should be)

pglablib/PgCollation.cpp

@@ -0,0 +1,2 @@
+#include "PgCollation.h"
+