Added flexability, handles colspans, window.resize event

[chprpipr]

Sorry for the reworked formatting. There are a few nuggets in this check in that I think are worthwhile:

• Takes colspans into account
• Clones and hides the original THEAD and TFOOT rather than removing them. This helps to preserve column alignment
• Inserts TH/TD elements to account for addition of scroll bar (preserves column alignment, particularly if the column is right justified
• Adds a window.resize event handler to update the table's display if the window changes dimensions.

[7--]

I used this version. Only difference I found is that the resizing works when the screen has been minimized and maximized again.