AG-315: multi columns for groups and hide groups when open
AG-315: multi columns for groups and hide groups when open

seanlandsman/ag-grid,ceolter/angular-grid,seanlandsman/ag-grid,ceolter/angular-grid,seanlandsman/ag-grid,killyosaur/ag-grid,ceolter/ag-grid,ceolter/ag-grid,killyosaur/ag-grid,killyosaur/ag-grid