Added new dataview event onDataUpdate which will be called always whenever the dataview updates.
Reason for new event:Existing events onRowsChanged,onRowCountChanged,onPagingInfoChanged are called only in the particular cases but we need a event which will be called always
dataview updates

Change-Id: I0ea007b2591f89436635412017aa1ba8bc993101
Merge "Added new dataview event onDataUpdate which will be called always whenever the dataview updates. Reason for new event:Existing events onRowsChanged,onRowCountChanged,onPagingInfoChanged are called only in the particular cases but we need a event which will be called always dataview updates"