pmset-simulator: fix tabs

Thanks to @MafooBristol in
https://github.com/nojhan/liquidprompt/issues/326#issuecomment-66104427
Battery/MacOS X: improved parsing

Parsing improved (faster, stricter), manually tested with pmset-simulator.
TODO: write automated tests.

https://github.com/nojhan/liquidprompt/issues/326
Battery/MacOS X: fix pmset parsing for tabs

See
https://github.com/nojhan/liquidprompt/issues/326#issuecomment-66104427