Add a mandelbrot parallel calculation WBE example

The mandelbrot calculation is neat example to provide
to show how the WBE engine can be used to compute various
calculations (the mandelbrot set in this example).

This will also create an image from the output if a filename
is provided and the pillow library is installed (that library
does the actual image writing).

See: http://en.wikipedia.org/wiki/Mandelbrot_set

Part of blueprint more-examples

Change-Id: I12b9b7a2ce61b17ddaa2930cc9cf266ae0c60932
Merge "Add a mandelbrot parallel calculation WBE example"