README.md: Misc updates
README.md: Misc updates

* Many changes to add clarification.
* Added "Click here" buttons which display text.  This significantly shortens the default view of the file, increasing the chance that people will actually read it.
* Removed unused, hidden text.
* Added hidden text for version 0.8.3.3 changes (will unhide when that version is ready).
thomasjacquin/allsky,thomasjacquin/allsky,thomasjacquin/allsky