inlineAggregate support

First cut of inline aggregate for #194.

When enabled, the aggregate header rows do not increment the row counter, causing the content rows to overlap with the header rows.  The content rows are then shifted with left: in .ngRow so the header arrows can still be clicked.

There are still things to be adjusted for things like the second grouping header, but it's a start.  To make the aggregate headers vertically aligned like the original issue, one can use aggregateTemplate to set top: or something similar.

![2013-05-01 11 23 53](https://f.cloud.github.com/assets/69736/449458/30cd9788-b273-11e2-90d0-adb1404de94b.png)