Quick references for older versions

[hahawoo]

Each release could have its own reference, for people using older versions.

For example: http://love2d-community.github.io/love-api/0.9.2/

http://love2d-community.github.io/love-api/ could still be for the latest version.

[rm-code]

Sounds good!

[hahawoo]

I've added: http://love2d-community.github.io/love-api/0.9.1/ http://love2d-community.github.io/love-api/0.9.2/ http://love2d-community.github.io/love-api/0.10.0/ http://love2d-community.github.io/love-api/0.10.1/ http://love2d-community.github.io/love-api/0.10.2/