Grids; Add 'Toggle' to show / hide hidden rows

When a grid has hidden rows (JavaScript code determines this), a "Show hidden rows" caption appeared in a light yellow bar below the grid.

Clicking this bar would show hidden rows and hide the bar.

This functionality has been changed so that clicking the bar will show hidden rows but then change the caption to indicate that clicking the bar again will re-hide the rows.

This bar still has a "close" button on the right-hand side however, once the bar is closed, you can now right-click the grid to toggle the hidden state of the rows.

NOTE: This brings the grid used in finPOWER Connect Cloud in line with a recent change to the HTML Widgets grid.