* defer patchmatch loading
Because of the way that patchmatch was loaded early at import time, it
was impossible to turn off the attempted loading with --no-patchmatch.
In addition, the patchmatch loading messages appear early on during
initialization, interfering with ability to print out the version
cleanly when --version provided to invoke script.
This commit creates a thin wrapper class for patch_match that is only
loaded when needed, solving both problems.
* create a singleton patchmatch object for use in inpainting
This creates a thin wrapper to patchmatch which loads the module
on demand, respecting the global "trypatchmatch" option.
* address 2d round of issues in PR 2039 comments
* Patchmatch->PatchMatch and misc cleanup
