responsive <table> style made with flexbox

[Wes1262]

goals:

• cells should be all flexible, no intrinsic width
• text-overflow support / marquee support
• scrollable tbody only with fixed thead/tfoot
• colspan support
• collapsible columns and colgroups

secondary goals:

• rowspan support
• nesting levels [screenshot]
• sortable columns

[Wes1262]

some blue sky thinking

• the datagrid should work with both <table> markup and <ul>/<ol> for more complex things; but, i'm not sure if tables' default style can be fully overrideable by css, in this case we should try to use some sensible markup
• flexible cells, scrollable tbody / colspan are pretty easy to do
• columns/colgroups styling it is not (position:absolute + z-index) and some JS will surely be needed
• as opposed to text-overflow, i wouldn't add native support for marquee but it should work without any issue at all and without forcing to add extra markup
• the whole thing should work transparently and it should not have any default behavior, so it has to be customizable, especially about collapsible and sortable columns (ie provide APIs for sorting rows/collapse columns instead of just implement them)