vo_opengl: fix broken rejection of extended scaling

Possibly explains why some users got mysterious FBO errors on crappy
hardware.
vo_opengl: remove inactive code
vo_opengl: remove requirement for RG textures

Features not supported are disabled (although with a misleading error
message).
vo_opengl: remove icc profile options from runtime-settable options

Because of the icc-profile-auto option (which was added at a later
point), supporting this would probably be slightly messy: the ICC
profile can spontaneously update, and then it would overwrite the
previously set options.

Don't make icc-profile-auto fatal if unsupported. The "auto" indicates
that it will use whatever it finds, even if it's nothing.

Also add a warning; before this commit, it just refused to initialize
without explanation.

As a mostly unrelated cosmetic change, remove redundant parameters which
had no point anymore.

Probably fixes #1359 (or rather works it around by disallowing it).
dvd: add the last chapter

As suggested in issue #1251. I think the main point is that it acts as
a hack to return to the DVD menu when jumping past the last chapter,
because it will reach title-EOF, instead of explicitly jumping to the
next file (which usually exits the player).

This basically reverts commit 8b7418d, except it doesn't include an
off-by-1 error (apparently).

Closes #1251.