Added test instructions
Rename quantization to quality

For parity between record and capture methods, quantization is now known
as quality (quantization still supported for backward compatibility
until 2.0)
Some recipe enhancements

Tweaked the threaded recipes to use sleep when their pools are starved
which significantly improves efficiency (turns out the main thread was
hogging the pool lock) and added some caveats to the capture while
recording recipe, as suggested by eldonT in #101.
Add recipe for multiple recordings
Fix up exceptions docs

Conflicts:
	picamera/exc.py
Fix #97

Mostly a documentation fix, but added some methods to PiCamera to
construct the image/video encoder required. Should now be possible for
developers to easily override the encoder class that PiCamera uses.
Correct handling of bitrate 0

Made modifications described in comments to #70 to warn about usage of
bitrate 0, but not to disable split_recording under any particular
circumstances.
Tidy up exceptions hierarchy

Added a few new subclasses of PiCameraRuntimeError, and removed __all__
from all modules (it's not necessary as there's nothing in the public
API which starts with _, and maintaining them just complicates evolving
the API).
Remove previewing fixture from certain tests

There's no need to test quite so many things with and without preview.
As long as the base functionality of recording and capturing works with
and without preview, the other tests can proceed with whatever preview
state the camera happens to be in.
Fix up PDF output

Latex won't use SVGs for images; have Inkscape perform conversions of
SVGs to PDFs for inclusion in Latex output
Change camera fix back to function scope

Module or session scope seems to lockup the camera rather easily with
the latest firmwares. Switch back to function scope until this can be
debugged