Updates the format of spans and make it the same with skips (position:row_spanxcolumn_span).
Add setSpans and setSkips to enable dynamically set values of spans and/or skips.
Add grid_rowWeights and grid_columnWeights to specify the proportional height of a row or a the proportional width of a column by providing the weights.
Update the layout of the activity_main.xml to demonstrate the usages of grid_rowColumns
Grid helper improvement part 1
activity_main.xml