Add command to exclude notes

[harmtemolder]

trafficstars

I’ve added a command to the command palette to add the currently opened note to an ignore list. That list can be managed from the settings tab. This could cover #4 and #6, I believe.

[harmtemolder]

@larslockefeer PS Of my 4 pull requests, it makes sense to merge this one first, because I’ve come to know your plugin a bit better by now and this includes improvements on what I did in the others