AUDIO block.
Merge pull request #38 from ignaciouy/audioBlock

AUDIO block.
update load init to use postprocess
general cleanup of breakage after conversion to post processing
use english in error messages (until we add i18n)
fix errors introduced to doShowCamera
set up proper values for camera, video when creating from palette
set dragging flag with turtle
sorted out block label value assignment issues
one more tweak to the block labels code for added robustness
fix problem with doubleflow rendering
fix bug in collapsible blocks regarding filler bitmaps
getStackSize needed to consider multiple children for doubleclamp blocks
use arrays for bitmap parts
populate all the artwork offsets
expand both flows in if-then-else blocks