Negation syntax or "include" syntax for new import "ignore" feature about boar HOT 4 CLOSED

The masks get applied* in sequential... 

Agreed. Possibly, this is even more useful for boar than an ignore list. I'd 
expect most users to really just want to store *.jpg or *.raw in a session, and 
ignore all other files. Luckily, this feature is easy to implement now that the 
ignore basics are in place. 

I think the most intuitive way to implement this would be to have an additional 
session property named "include". And if it is set, boar will ignore all other 
types of files. If both "include" and "ignore" is set, then "ignore" will have 
priority. That is, you include "*.jpg" but you ignore "tmp/*", it behaves as 
you would expect. Intuitively it feels like that system would fit most users. 
Any thoughts about this before I implement it?

Implemented in changeset d32306c81251.

Sounds good to me. And yes, as you do, I expect in most cases people want to 
process only a certain type(s) of files to the exclusion of all else (just 
images, just videos, etc). That said, keeping the ignore parameter for things 
such as tmp files and the like is important as well, so in other words, your 
implementation seems just fine.