Interface unification proposal

[dstrozynski]

The interface for removing rows looks like this:

handsontable('alter', 'remove_row', index, [toIndex])

and the interface for adding rows looks like this:

handsontable('alter', 'insert_row', index)

It would be good - I think - if it could be more unified in the form of:

handsontable('alter', 'remove_row', startIndex, [numberOfRows])
handsontable('alter', 'insert_row', startIndex, [numberOfRows])

[warpech]

Good idea. I will implement it soon.

[warpech]

This is now implemented in Handsontable 0.8.11. Thanks for the inspiration. Please test it if you happen to have some free time :)