Some & -> && fixes.
Screen: Really don't use AUX buffers if disable requested.

The kPsychDisableAUXBuffers setting is honored in the sense that no AUX
buffers are requested. However, this equals requesting a visual with >=
0 AUX buffers, as zero is the default. On GPU's where all visuals have
> 0 AUX buffers this means we get an AUX buffer we didn't ask for. If
code later uses aux buffers if any available, it will use them despite
our disable. -> Check for no-aux-buffer request before use of aux
buffers, not only at context creation time.

This is a minor, practically irrelevant change, just needed for
debugging something. Therefore we won't rebuild mex files for it.
Screen/Linux: Improve buffer_age filtering.

EXT_buffer age queries work mostly as expected :-)

Filter out zero case --> Can happen due to driver optimizations, not an
indication of failure.
Value 1 --> CopySwap due to redirection due to compositor activity -->
Finally something that really tells us if a compositor is interfering
:-).
Value 2 -> Double-buffering -> everything good.
Value > 2 -> Triple/n-buffering: Fatal for timestamping.

Now we filter out non-fatal values and give some useful help for known
values 1,2,3,...,n.

Screen for 64-Bit Octave on Linux rebuilt and tested with latest NVidia
binary driver beta release. Works!
Screen mex files for Linux rebuilt with latest improvements.

Screen for 64-Bit Matlab, 32-Bit Matlab & Octave, 64-Bit Octave was
already in previous commit.
All improvements are Linux specific, so no need to rebuild other
platforms. Mex files are ready for release.
Screen/Linux: Remove Intel-SNA workaround - It didn't work around :-(

Doesn't have expected effect, probably due to other bugs in SNA. Causes
a complete graphics system hang instead.

So situation now (further testing pending) seems to be that the latest
2.20.16+ drivers work well if Option "TripleBuffer" "Off" is specified
in xorg.conf, and don't work in any meaningful way for us at all if the
option is omitted.

Also add some more references to help SyncTrouble - Linux section.
Screen for 32-Bit Octave on Linux rebuilt for testing.
Remaining Screen mex files for Linux rebuilt.

64-Bit Octave, 32/64-Bit Matlab rebuilt.
32-Bit Octave already in previous commit.
This is the final set of Mex files for the beta release. Everything
tested to death. Intel gpu's now work reasonable ok:

With the broken drivers (v2.20.15 and earlier), UXA works well:
Triplebuffering is detected and reported to user with info what to do.
Broken swap scheduling is detected and automatic fix applied which
fixes it perfectly reliably - although at cost of slightly lower
performance under heavy load. SNA is hopeless: Gets reported as broken,
but absolutely no way to fix it - except for a driver upgrade.

Intel drivers of v2.20.16 and later (source release at 15th December
2012) are bug-free wrt. to swap scheduling and timestamping for our
purposes. Screen handles them properly, both with UXA and SNA path.

Tested on HP Mini Atom Netbook (Dualcore Atom 1.6 Ghz, 2 GB RAM, Intel
GMA-950 / Intel 945 GME chipset, aka Gen3 hardware), tested on 32-Bit
Ubuntu 12.10 with 2.20.9 driver of distribution and with self-compiled
2.20.17+ driver from current intel master repo.

-> Mex files ready for release.
Some documentation updates...