Tweak logging behavior with --report-plist as arg

Send status updates to stderr when autopkg is invoked with --report-plist
result_report written to plist file

instead of stdout.
require file to be specified.
Merge commit '62e71ef4f92596f45e4edf07172b4174983db3f2'

* commit '62e71ef4f92596f45e4edf07172b4174983db3f2': (48 commits)
  pylint cleanups for autopkglib/Versioner.py
  pylint cleanups for autopkglib/URLTextSearcher.py
  pylint cleanups for autopkglib/URLDownloader.py
  pylint cleanups for autopkglib/Unarchiver.py
  pylint cleanups for autopkglib/Symlinker.py
  pylint cleanups for autopkglib/StopProcessingIf.py
  pylint cleanups for autopkglib/SparkleUpdateInfoProvider.py
  pylint cleanups for autopkglib/PlistReader.py; also use the filtered list in PlistReader.find_bundle(path): previously this was generated, but ignored.
  PyLint cleanups for autopkglib/PlistEditor.py
  PyLint cleanups for autopkglib/PkgRootCreator.py
  PyLint cleanups for autopkglib/PkgPayloadUnpacker.py
  PyLint cleanups for autopkglib/PkgInfoCreator.py; also raise ProcessorError if there is a request to make bundle-style info
  PyLint cleanups for autopkglib/PkgExtractor.py
  PyLint cleanups for autopkglib/PkgCreator.py
  PyLint cleanups for autopkglib/PkgCopier.py
  PyLint cleanups for autopkglib/PathDeleter.py
  PyLint cleanups for autopkglib/MunkiPkginfoMerger.py
  PyLint cleanups for autopkglib/MunkiInstallsItemsCreator.py
  PyLint cleanups for autopkglib/MunkiInfoCreator.py
  PyLint cleanups for autopkglib/MunkiImporter.py
  ...

Conflicts:
	Code/autopkg
Let FoundationPlist.writePlist() handle file access testing
remove option.verbosity = 0 that snuck back in during merge
plist-write def with a sys.exit for re-use by --report-plist

- should close #104
- update docstring and option style