* fixed more margin code. we're inching towards correctness.
* the width contributed by a colspanning cell is now proportionately distributed to the columns based on the columns "effective width"
* added logic for handling illegal COLS attribute on a table (like COLS=4 in a 3-column table). See nsTableFrame::GetEffectiveCOLSAttribute()
* added logic for handling illegal COLSPAN attribute on a cell (like COLSPAN=4 in a 3-column table). See nsTableFrame::GetEffectiveColSpan(). This is wrong, and will get reworked soon.
* added the ability for cell width attributes to effect column width like Nav4.
this work exposed a few bugs and slow spots, which have been fixed
for the aol page, I added some additional backwards compatibility code
to proportionately distribute width when a fixed-width cell has colspans
