Ensure that parallel parsing sbs calls pass on --no-depend-generate and --no-depend-include (as these influence makefile generation). Make .DEFAULT a double-colon target, so we don't have to worry about duplicate instances due to -include. Code review updates.

#!/usr/bin/env python
"A script for invoking coverage from the command line."

import sys
del sys.path[0] # Otherwise "import coverage" finds this file!
import coverage

coverage.the_coverage.command_line(sys.argv[1:])