logic changes for selection cancellation

[Doublonmousse]

Fixes #414

• This fixes the small dots that appears on selection cancellation with the pen (whilst allowing for strokes to still be written if they're larger than small dots)

A couple remarks :

• shapes need an additional up/down cycle : we could change it to follow the same logic as the brush but this could also be done by not changing the logic of the shape part and only disallowing shapes to be too small (in that case we can create shapes that aren't even visible but are still part of the document)
• the eraser and typewriter both need an additional pen up/down to activate
• tools aren't affected (they won't change anything if they're activated on such a short pen down/up cycle)
• This does not change behavior when a selection is deleted.

[Doublonmousse]

I've added a condition to only create shapes if they're large enough. As things like arrows would still appear on a single pen event, I'll leave the current behavior for shapes after a selection cancellation (that is we need an extra up/down cycle)

[Doublonmousse]

I've added the cancellation of the selection tool upon deleting a selection when the selection tool is temporary

[Doublonmousse]

Putting back in draft as this needs a little work before it can be merged.
I'm wondering if the condition can be slightly modified to include time delay as well. It will cancel a dot after a selection but sometimes this dot can be large enough to stay (if the pen slides a bit instead of a clean hit)