menu-cache should be optional

[agaida]

default to off - only a reminder

[tsujan]

I think menu-cache isn't optional in libfm-qt. We should wait until @PCMan ports that part to C++.

[PCMan]

It's required at the moment.
The application chooser dialog and menu:// URIs are using that library.
Unless we make these related features optional it's hard to remove.

[tsujan]

Unless we make these related features optional it's hard to remove.

Or making them not depend on menu-cache; I think that may be possible.

[agaida]

right now the dependency don't hurt - we removed the big impact of menu-cache in the panel. But it would be fine to get rid of menu-cache completely.

[tsujan]

→ #417