Fix some of memory leaks.
Add try/catch for fetch.

It is possible for the cursor fetch to process interrupts.
Try not to evaluate META_VAR if not necessary.

Suggested by Peter Eisentraut.
Remove use of gettext.

It could be a problem when libintl was not found.
Report and patch by Peter Eisentraut.
Implement fetch(n) and move(n).
Update documentation.
Tag 1.4.0
* Fix compilation with latest v8 3.18.x