move get_optimize_after() into its own function.
handle absolute paths on the command line.
by also getting their timestamp info correctly.
remove some cruft.
Only store timestamps for full top directories recursed into.
only record timestamps if we recrused into those directories
remove unused options variable form get_image_format until variable
verbosity is implemented
only remove timestamp files if we're going to write another one.
add docstrings to several functions
pylint
add more TODOs
increment version to 0.11.0
run picopt twice in the test to check for timestamps