Improve performance of direct paragraph styling

Avoid creating a lot of unnecessary styles, and batching up calls to canvas size redraws provide a decent speed boost. This still is not very responsive @ 1000pages unfortunately, as it is now limited by step counting performance (49049ms).

# Performance
@100pages.odt
*Note, to run this benchmark before the fix, include the url parameter includeSlow=true. e.g.: http://localhost:8124/programs/benchmark/src-index.html?includeSlow=true*

|                                 | master (957dee3) (ms) | pr minus process batch (ms) | pr (ms)|
|----------------------------|--------------------------------|-----------------------------------|--------|
|Align the current selection 'justify'|err*|10482|3071|

* Master is unable to complete run as Chrome keeps hanging and asking to kill the unresponsive page.