Changes:

Changes:
- Added command-line option -f, which enables a full check. Changed
  behavior when -f has not been specified to running checkpatch, sparse
  and headers_check only. This makes the script complete a lot faster.
- A summary of the errors and warnings reported by checkpatch, sparse
  and make headers_check is now printed.
- Made the functions kernel_version and patchlevel more robust.
- The function duplicate_source_tree now only copies the files
  administered by Subversion. Other files, e.g. .o files, are skipped.
- Moved the make flag -j3 from individual make commands to a single
  assignment to the variable MAKEFLAGS, such that the make flags are
  easier to modify.

git-svn-id: https://scst.svn.sourceforge.net/svnroot/scst/trunk@709 d57e44dd-8a1f-0410-8b47-8ef2f437770f