convert dashboard progress bars to jqueryUI 

as mentioned in Bug #1344 - I have made a start of moving some progress bars over to jQueryUI.

It will need some testing as I don't have swap or temp on my box to test.

The CPU progress bar is initialised with a false value:
 
```jQuery("#cpuPB").progressbar( { value:false } );```

This results in an empty progress bar ie value 0 for the 1st 10 seconds. If/When jQueryUI is bumped up in pfsense to 10.x then this will display the Indeterminable progress bar for the 1st 10 seconds while it waits on ajax. An example of Indeterminable progress bar can be seen here:

http://jqueryui.com/resources/demos/progressbar/indeterminate.html