Implement new buffers from Test.
*Improved buffer handling with minimal overhead
*Easir extension of the buffer class
*C-allocated memory prevents lua memory limits
*Garbage collected memory, with optional clean() if needed

Adapted imgops, process code and ppmtools to work with the new buffers, not all functions are tested properly yet! Current test-case is fully functional.

Additional bugs fixed to handle GS buffers better.

Changes to Copy/New methods, type field is deprecated.
Cleanup
Handle single/double precision
Add reference for new buffer calls
Add erosion/dilation operations
More morphological operations using new buffers
Typo
Merge branch 'refs/heads/C-buffers'