Select squirrel cache via CVS2GIT_SQUIRREL_DIR
reimport.sh: match paths to cvs2git-funcs.
Use cvs2svn-2.4.0 from mg13's space.
Optionally kill off specified branches.

Partial cherry-picked of 4a1a2b28
 but don't commit project-specific kill list
reimport.sh: fix HAS_NOCVS logic.
there is no need to commit the *.known-good.txt files
except as examples of what they should look like
Use cvs2git.options file instead of command line args.

Partial cherry-pick from f6ab24d0

Don't impose our cvs2git.options on others,
 see branch "anacode" for ours
Merge branch 'dev/cvs2svn240'

* dev/cvs2svn240:
  Use cvs2git.options file instead of command line args.
  Use cvs2svn-2.4.0 from mg13's space.

External options file is necessary for cvs2git 2.4.0
 also possible but not necessary for 2.3.0
 we don't ship one on "master"