Frame first steps.

This composites one possibly-transparent image over another
possibly-transparent image. All interesting image manipulation
happens in C. This is unlike the existing watermark.py filter,
where the image is constructed in two phases (alpha and paste).

I haven't yet implemented 9-patch stretching; I'm saving that
for a follow up.
Merge pull request #1 from square/jwilson/frame

Frame first steps.
handle for issue #105 add tests on thumbor.handlers.image
Merge pull request #106 from dhardy92/testHandlerImage

handle for issue #105 add tests on thumbor.handlers.image
Implement Nine Patch arithmetic.

This cuts up the frame into boxes and pastes those boxes
over the appropriate region of the target. At the moment
the boxes aren't stretched; that's a follow up.
Merge pull request #2 from square/jwilson/ninepatch

Implement Nine Patch arithmetic.
Use bilinear interpolation to scale stretchy regions.
Fix #105 and tests passing now
Merge pull request #3 from square/jwilson/scale

Use bilinear interpolation to scale stretchy regions.
Support padding frames.

This supports padding on either side of the frame:
 - Left padding of 10 moves the framed image 10 pixels to
   the left. This allows for thick frames that don't obscure
   any image content.
 - Left padding of -10 moves the frame 10 pixels to the left.
   This lets the frame sit inside the framed image.
Merge pull request #4 from square/jwilson/padding

Support padding frames.
Padding informed by 9-patch.
Merge pull request #5 from square/jwilson/padding2

Padding informed by 9-patch.
Merge pull request #107 from square/master

New frame filter that uses nine patch PNGs
Adding support to optional parameters in filters.

You simply have to define a default argument to the corresponding
parameter in the filter function and voila it's optional in the URL.
Fix a silly mistake with padding.

I flipped the right and bottom padding when passing from
C to Python. Ugh!
Merge pull request #108 from square/jwilson/flip

Fix a silly mistake with padding.
Rename configuration variables for upload
Added support to config aliases
Adding some more tests to config aliases