Unnecessary float in onecol.css can play havok with other theme elements

After spending some time trying to track down why a region/block I was trying to float:right wasn't working I discovered two things:

1) There are float, overflow, and width settings in onecol.css which do not serve any discernible purpose and which greatly mess up the ability to float other theme elements with the content area. Looking at the original onecol.css I'm guessing that the values were simply brought over from another multi column css file at some point - since the values do not make sense for a one column panel in most cases. Attached is a patch which deletes the problem attributes of the selectors, but leaves the selectors themselves in place just in case someone does want to do something with them. (hence one has 'options' instead of 'restrictions')

2) There is in fact an advantage to using one column layout vs. using a 'flexible layout' which has a single row and one column (I used to think they were roughly equivalent). Namely, one can't get rid of the float which exists by default in all 'flexible layouts' css -- which creates the exact same problem as having the float in onecol.css.