minor tweak in the output of appleseed.cli -h.
fixed parsing of valued command line arguments supporting multiple occurrences (such as the -p parameter in appleseed.cli).
cosmetics.
fixed bug introduced in f75b987efb8301af5277476f9164227db9d00f61 ("simplified the code by making the const version of renderer::TransformSequence::earliest_transform() return an identity transform if the sequence is empty") and simplified the renderer::TransformSequence API.