Implement custom DPI settings for PDF output

Use this by calling beginRecord(PDF, "filename.pdf", dpi). The default DPI remains at 72.
Image transparency for PDF output

Before, drawing an image with transparency would result in black, opaque pixels in the PDF file. This change, figured out together with Jürg Lehni, fixes this. At its core, switching from drawImage(img, int, int, int, int, int, int, int, int, null) to drawImage(img, int, int, null) seems to do the trick - so this might have been a bug in iText all along.

Signed-off-by: Jürg Lehni <juerg@scratchdisk.com>
Signed-off-by: Gottfried Haider <gottfried.haider@gmail.com>
Merge branch 'pdf-custom-dpi'
removed use of switch/case
setBackground for (JFrame)frame

frame.setBackground >> ((JFrame)frame).getContentPane().setBackground
Merge pull request #2072 from kamedin/master

frame.setBackground in PApplet
misc fixes, todo updates
Merge branch 'master' of github.com:processing/processing
misc fixes, todo updates
fix formatting
continue with the refactoring of PGL
change build scripts to use built-in ecj (removes jdk req)
Merge branch 'master' of github.com:processing/processing
making swap public
adding tweak to avoid crash when tools or modes folders are inaccessible
done with the PGL refactoring
added registerListeners() method to PGL
check for null canvas
added GLW library for native window output using NEWT
updated library name in example