Magic Wand Tool Overhaul

[MorrowShore]

Magic wand could use a series of adjustments to become a better tool.

A- Defaults:

A1- Default tolerance should be 22~26
A2- Default feather should be 1px
A3- Size limit default should be the entire canvas / disabled

B- Behavior

B1- Modifier keys + mouse scroll could be used to adjust parameters (such as size limit, if A3 is opposed)
B2- There should be an option to disable confirmation prompt for Magic Wand and fill tool, or alternatively, allow addition, reduction, manipulation, and inversion of the confirmation prompt itself (before confirming) which would practically be the same.
B3- Magic wand {left click, hold, and drag to left or right} should adjust tolerance in real time by units of 2 and update selection.

B4- The selection demonstration during confirmation prompt should not have a popular color such as blue, but should instead be assuredly distinguishable from the image.

C- Performance

Considerations to improve magic wand performance are being made.

[askmeaboutlo0m]

A1 and A2 are arbitrary values that wouldn't be useful for many applications, like trying to select inside linework or for hard-edged lines. Leaving them at zero and letting the user adjust them makes more sense rather than leaving them scratching their head at which of the six sliders is making the borders blurry by default.

A3 is implemented.

B1 is a matter of canvas shortcuts and is already possible for the size limit. B2 and B3 are implemented. B4 is split off into #1396.

C is implemented.