NEWS for 0.91-2 (with respect to 0.91-1)

- made [pix_freeframe] not crash on OSX (fixes #2476663)

- do not use libTIFF/libJPEG is ImageMagick++ is present (fixes #2449674 & #2506838)

- always use RGBA for image-loading on OS-X (fixes #2484087)

- check for gl/glu headers (fixes #2032488)

- force focus when drawing without borders on X (fixes #2192358)

- only use multitexturing if hardware supports it

- windows-installer adapted to new svn-layout

