Augment got_patch_progress_cb by providing the hunks that were applied with offset (or that failed) and the recoverable error encountered during the operation (bad status, missing file, ...) got_patch now proceeds when a file fails to be patched and exits with GOT_ERR_PATCH_FAILED if no other errors are encountered. While here, also add a test for the 'hunk applied with offset' case and shrink test_patch_dont_apply and illegal_status by taking advantage that 'got patch' doesn't stop at the first error. (And add some other cases to illegal_status too.) discussed with and ok stsp@

This introduce a proper got_patch specific progress callback that is invoked after processing a patch. It also drops the hackish printf in the modified case and takes `nop' out of the struct got_patch. ok stsp

with lots of help from stsp for the manpage bits!

Don't allow `got patch' to delete files that are not known, or add files that are already known and to edit files that are known, not obstructed and without conflicts.