v1.1 release.

This is a bugfix release. The registry is updated, which includes fixes to some enums from Khronos. Build fixes are included for 32-bit linux, --as-needed, and apps that link without pulling in libdl themselves. Also, GLES1/2 apps on systems without GLX are fixed.

Thanks go to Matt Turner for the --as-needed fix, to Daniel Kurtz for testing the library on a very different system from mine and filing bugs, and to Julien Cristau for reviewing the v1.0 debian package.