Fixing 1288

[hkaiser]

This adds 2 new performance counters (see #1288 for details)

[hkaiser]

@pagrubel, @rajrekha85: Please check this branch out and report back whether those counters do what you requested.

[hkaiser]

via IRC:

[19 Oct 14 15:42] * Rraj * hkaiser: The hierarchy scheduler is working fine for 
pending accesses, pending misses, stolen from pending, stolen to pending. 
Now the stolen from staged and stolen to staged are zeroes!

[hkaiser]

From looking at the code: the hierarchy scheduler does not steal staged tasks. Thus all is well.