Sabotage Window/Tab Switch Visibility

Make website completely invisible to the user switching to another window or tab. May break some websites.

v0.0.3 30/06/2024
- nothing really changed other than added comments and documentation
- fixed some grammar in the greasyfork description
v0.0.3 29/01/2024
- fixed visibilityState returning false instead of "visible"
v0.0.2 29/01/2024
- code clean up
- fixed bug where "safe" block listed event callbacks are not called
- added "on{event}" blocking for element prototype
v0.0.1 28/01/2024