RFC: drop bevel

Since we are redoing border anyway, bevel (which is just a form of 
border) seems somewhat redundant.

The properties form and thickness can be easily incorporated in a name 
which can be grafted to the desired root directory where a borders (now 
broken-up) images can be found.

<border name="bevel_1_up" />

Any objections?

On a related note: bevel_1_up or bevel1up?

- Charlie