Screen: Fix formatting of PsychVideoCaptureSupportLibDC1394.c

Make it less ugly by fixing indentation etc. Also remove some
superfluous fflush()es along the way and suppress two false
compiler warnings to get a clean compile.

-> Screen for 64-Bit Octave on Linux rebuilt and tested.
Screen: Add pixeldepth 5 "YUV" support to libdc1394 engine.

So usercode can explicitely request YUV capture from a camera
to save bus bandwidth on the firewire bus.
Screen: Make framerate calculation in firewire mode 7 less wrong.

Don't have a camera that doesn't report bogus values, so this
is probably still wrong and only the fallback path reports
correct values. However, the old formula was definitely wrong,
so this is less wrong.
Screen/OSX: Add AppNap protection et al. for OSX 10.9+

Whenever Screen() gets initialized, AppNap protection is enabled.
Whenever it gets clear'ed, AppNap protection is disabled. As Screen()
is also called by Priority() on OSX, this will imply protection for
anything visual and anything using Priority() to imply it is timing
sensitive.

What does it do? On pre 10.9 nothing. On 10.9+ it uses the new
"Activity" API to tell the OS to prevent or enable certain
actions/optimizations to make sure the system doesn't go to sleep or
nap, or the display doesn't go to sleep or nap, or the application
isn't starved of cpu cycles (=forced to nap) during PTB operations. It
also tells the OS that this app is "NSActivityLatencyCritical".

We somewhat abuse th api's here, which will lead to shortened battery
life as long as Screen() isn't flushed, but correctness is more
important than battery life, and i don't have time or nerves to think
of a more intelligent and balanced approach. Better safe than sorry.

-> Screen for 64-Bit Matlab and Octave on OSX rebuilt and tested.
-> While it seems to work and doesn't seem to cause problems i also
can't see any measureable benefit in timing behaviour. On my machine
OSX 10.9 just sucks display-timing wise and i haven't tested other
modalities.
Merge branch 'master' of https://github.com/kleinerm/Psychtoolbox-3
Screen: Add multi-camera sync support to dc1394 video capture - Part I

This is the control code for starting and stopping synchronous
capture + setup code in 'SetVideocaptureParameter' for selecting
master/slave role and sync strategy.

We allow:

a) Software sync: Start/Stop on a best-effort software basis.
b) Firewire bus sync via broadcast of iso on/off signals from master.
c) Hardware sync via trigger cable.

For c) the setup code for trigger source/mode/polarity is still
missing - tbd.

-> Tested for basic function, but sync precision testing is tbd.
-> VideoMultiCameraCaptureDemo updated to allow multicam sync testing.
-> Screen for Octave on Linux rebuilt and tested.

This is part I of sync support.