Drupal 7 fixes for graphael and graphael_example

Hey,

I found a few issues in the graphael module trying to get it to work with the example. The attached patch fixes them:
* hook_theme should use 'variables' not 'arguments' (graphael.module)
* The was settings are accessed in javascript has changed in D7 and needs to use "attach:" (graphael.js)
* The theme() call uses different parameter format now (graphael/graphael_example/graphael_example.graphs.inc)

I was able to get the graphael_example/ page rendering properly with these fixes.