[Scale; 1.8] Fine-tune some aspects of Scale

[autarkper]

1. Don't let Scale react on spurious pointer-motion events that arise from the opening animation.
2. Let the close button more closely follow the focused window, be it keyboard- or mouse-focused.
3. Scale should open with the close button enabled for the default-selected window.
4. Windows should be sorted similar to Alt-Tab, most importantly: minimized windows should be pushed back in the order.
5. Ensure that windows and overlays never go out of sync.
6. Use all available horizontal space for windows captions.
7. Adapt window-caption width as the selection changes and window titles are updated.
8. Make Scale usable with many monitors.
9. Window context menu.
10. Lots of other enhancements.
11. Lots of code removed.

Current status: Begs to be tested.

[Xethron]

Ah! Perfect! Works perfectly. Been waiting for this commit. See no errors thus far.

[autarkper]

This now contains all my Scale-related work on my master branch.