Use drop chance correctly

Given that `randf` output is in the range [0, 1] inclusive, and we want `chance = 0` to mean never, and `chance = 1` to mean always, we need to worry about the edge cases.

We need the `>=` because when `randf() == 0` and `chance == 0` just using `>` would give us the wrong result.

We need to compare against 1 because when `randf() == 1` and `chance == 1` we would get the wrong reasult due to the `>=`.

This is the from I found easier to read.

Fixed dialogue path

The dialogue forlder was moved in 426a3b18

Update gitignore file

Fix comment-reformatting spillover

Fix #190: Enabling Pixel Snap

Level up on experience change; fixed type mismatch

* Added Popup for missed skills

* Fixed signal name, reduced Builder and label Popups.

I started refactoring the code to make it easier to follow. This removes some
unused signal, makes some names more consistent and the code a bit easier to
read.

The Game node shouldn't be responsible for updating the party after an
encounter: the party should update itself.

- check press-only mouse (left-button) & touch input events

closes #169