Fixed steps in autoSizeColumns() that detects infinite loops for shrink and grow operations.  In some cases the prevTotal exceeded total (for grow) and was less than total (for shrink).  The existing check simply checked if the 2 values were equal, but not if prevTotal had gone beyond the proper bounds, resulting in an infinite loop.
Merge pull request #818 from mjonas87/master

Improved infinite loop avoidance in autoSizeColumns()
Implement lazy totals calculation in the DataView.

Add a ‘lazyTotalsCalculation’ grouping info option (default = false)
that delays the totals calculation until the item is accessed via
getItem(index).  This can dramatically improve the perceived
performance of the DataView operations on very large datasets.
Optimize DataView group collapse/expand.
Fix a typo