Moved persist column styles from table.columntoggle.css to table.skin.cs...

I updated the css files organization by moving some ".tablesaw-swipe .tablesaw-cell-persist" classes from tables.columntoggle.css to tables.skin.css.

This results in them being excluded from the tablesaw.bare.css file as one would hope for, making those tables more consistent.

This resolves the main code/appearance complaint form Issue #71 There are still documentation concerns in that issue which need to be addressed, but that can be done separately.