toplev: Implement metrics, update to full 2.5 model

Update to a new TopDown 2.5 model
Add a --metrics argument to print metrics
toplev: Add experimential sample option

Suggest potential sample points.
toplev: bug fixes for last changes
tl-barplot: Minor output tidying
tl-barplot: reduce hspace for smaller font
toplev: Add --graph option to directly call tl-barplot

No live plotting yet.
Merge branch 'toplev-pipe'
Merge branch 'master' of ssh://github.com/andikleen/pmu-tools