Feature: rowSpan and colSpan

[m-abs]

Similar to using the GridLayout it would be very useful to let a single item in the grid span more than one row or column.

Relates to #30

[PeterStaev]

Done some research and seems with the default provided layout managers for both iOS and Android this will not be possible. So a custom layout manager should be implemented.

Android: https://stackoverflow.com/questions/37006115/android-recyclerview-with-gridlayoutmanager-make-item-span-multiple-rows

iOS: https://github.com/PeterStaev/RFQuiltLayout