Prevent privilege escalation in explicit calls to validators
Update Changes.
9.4 support with minor API change.

Patch by Michael Paquier.
Fix off-by-one in variadic .execute handling
Remove exception specifier from PG callbacks.

9.4 includes function declaration in PG_FUNCTION_INFO_V1 macro, which is
not compatible with ours using exception specifiers.  Actually I don't
see the reason we have them so simply I remove them.
Add .gitignore in folder

This will prevent unfortunate commit of unwanted files.
Correct check in plv8.return_next.

The same logic is borrowed from window function API.  Per report #88.