[ptx] Enblend bugfixes

[Andrew C Mihal]

I put version 1.1 on the webpage.

http://www-cad.eecs.berkeley.edu/~mihal/enblend

This release has bugfixes for two problems that were causing artifacts in 
the output image.

The first problem caused a patch to appear that looked dark and sometimes
shifted relative to the area underneath it. The patch is actually an
unmodified segment of an input image where it pokes out from the far side
of a blending region-of-interest zone.

The second problem would cause perfectly horizontal or perfectly vertical 
seams to appear. This turned out to be a boundary condition problem with 
the Laplacian pyramids.

Thanks to everyone who submitted bug reports and sent me example images. 
Keep them coming.

Andrew

---------------------------------
Andrew Mihal
www-cad.eecs.berkeley.edu/~mihal
mihal at eecs.berkeley.edu