Fix the game being basically broken due to multi-admin, by porting over some missing changes from Kart

Use Joystick 1 and Joystick 2 by default if plugged in

See merge request !364

Joystick juggling

See merge request !355

Slightly re-organize DLLs and document the required list for bundling

See merge request !365

Make uninstaller a self-extractable

See merge request !367

Tiny Makefile Fix

See merge request !289

Add old-install-list.txt to explicitly define which old install files need to be moved

See merge request !366

Replaces MoveOldExeDlls routine in installer staging

Reason for this is because the SDL2 binaries live in libs/ for ease of copying. The DLLs ought to be in one location.

https://github.com/jrfonseca/drmingw/releases/tag/0.9.0

Update OSX icon

See merge request STJr/SRB2!363

Controller select menu improvements.

See merge request !354

Joystick additions for menu, axis defaults, and vertical look toggle

See merge request !359

Make mappable buttons for System Menu, Screenshot, Movie, and Viewpoint

See merge request !358

CMake:Use commit hash and branch name.

Closes #37

See merge request !360

Forgot a gitignore

See merge request !362

Installer followup

See merge request !361

* Check if administrator rights are required
* Add INSTALL INSTRUCTIONS text file to root install folder in case the installer fails
* Add failsafes to uninstaller file deletion: check if name is a folder, and check for illegal chars
* Fixed parentheses breaking the installer by instead making exclamation marks do the breaking. Thanks Windows!

This reverts commit 9de31cf2.

* Add "Pause" entry to multiplayer control panel to give joy users a way to pause in netgames