Fix multiple profiles with same output filter filename

[Apollys]

Currently, the backend loads the output filter rather than the input filter, if it exists, to save computation.

Since all profiles by default have the same output filter filename, we need to ensure the output filter actually corresponds to the current profile. If not, we need to read the input filter.

• A simple option is just to always read the input filter.
• Otherwise, we can label the output filter with the associated profile (example: make first line a comment that contains the profile name). Then validate this on load.

[Apollys]

Fixed with the following workflow (see big right box), except we skip step 1.