Updates to mandelbrot demo.

mandelbrot.html:

  * Moved Copyright info down below html head so that the charset
    declaration occurs within first 1024 bytes of page.

  * Removed unneeded references to prototype compiler js support code.

  * Added area for sequential variant to render (for comparison)

  * Added area for Javascript to report timing statistics

  * Removed explicit source code in html (make Javascript spit it out
    instead).

mandelbrot.js

  * Added ParallelArray-to-Array conversion routine

  * Fixed code to use more recent ParallelArray interface
    (e.g. callback takes (x,y) as separate argument rather than
    packaged in an array tuple).

  * Gather timing statistics (and emit them on webpage).

  * Spit out the source for the kernel into the calling webpage.