Commit 45c24100 (LOK: change type of
view ids to uintptr_t, 2016-06-17) fixed the problem of view IDs being
reused for the price of random IDs, which makes debugging harder.

Implement a simple shellToView() function that makes sure view IDs are
not reused, and stop exposing view shell pointer addresses, which allows
reverting the LOK API change.

Change-Id: I63089e6de08ee7e1c7706757d43a11f6cf4d6e06
Reviewed-on: https://gerrit.libreoffice.org/26773Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>