pm-graph: config files and installer

- name change: analyze_boot.py to bootgraph.py
- name change: analyze_suspend.py to sleepgraph.py
- added config files for easier sleepgraph usage
- added example.cfg which describes all config options
- added cgskip.txt definition for slimmer callgraphs

Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>