Add context switch metrics

Add entries from /proc/<pid>/status for:

voluntary_ctxt_switches
nonvoluntary_ctxt_switches
Fill out remaining fields in /proc/<pid>/stat

The following fields were added from stat:

rt_priority
policy
delayacct_blkio_ticks
guest_time
cguest_time
Merge branch 'martins-working' of git://github.com/ubccr/pcp into martins-merge
Merge branch 'martins-merge' into dev
Update regex in qa/370, missed on earlier commit
pmdaproc: test updates for new metrics, rename ticks to time