Revert to levels increasing in z.  This is necessary for amrclaw graphics
Some preliminary matlab graphics tests
Stray 'then' found its way into a conditional statement...
Added 'ForestClaw' flag to allow for slight differences in the way that ForestClaw and AMRclaw handle 2d amr plots
Make 'readblocknumber' an optional argument
masking of amr levels now depends on whether ForestClaw or AMRClaw is being plotted
Added blockno argument to add_patch2slice.  By default blockno is set to 0, if only a single block is used