Italian translation updated
(cherry picked from commit 0eb31ac6e44060d63429630100ac74052c6ce3e0)
Prevent users from unintentional image overwrite
(cherry picked from commit 7849da547fe0f885d807d18af6948e3fb76afbf5)
Early bailout in calculator on empty formula
(cherry picked from commit 1e34d10e9d0b50117dd58514cd1a518d7d544433)
Add support for calculator formulas in conf

This is needed for cache_memory to be a nice looking value in the XML*.
If it turns out to be too slow we have to revert and remove the formula
from the XML file*.

* data/darktableconfig.xml.in
(cherry picked from commit 7e445c328e86f03cae8e0eed4dc6a742cacb9745)
Fix overexposed borders to be float instead of int
(cherry picked from commit 7cb492d42becf08330814712288886809fe9fd4f)
Remove hardcoded default settings from the code

... these are all in the XML and default darktablerc now.
(cherry picked from commit 4c9d781e73d7874338b864919411c754815b5934)