Removed the word "focus".

Removed the phrase "to have the focus" from README.md.
Windows don't have the focus, they are active.
Removed package Util from the application map.
Cleared up importance of the active window.
Added an FAQ to the repository.
Tweaked the "caption of the window under the cursor" text box.

The box now is enabled, read-only, and borderless.
It now gets only updated if the caption changes.