Add a section to README referencing the INSTALL file.
Repair fallback mechanism

We don't "require" SDL2 strictly, we'd just try out the sdl1 version.
Merge pull request #1096 from stefanbeller/master

Add install section to readme, repair sdl detection fallback mechanism in cmake
Add a script to regenerate the Attributes reference wiki page
Change destination of the Attribute Reference page created.
Merge pull request #1097 from stefanbeller/master

Add a script to regenerate the Attributes reference wiki page