Update CLP from other software.

- Add Clp_vsnprintf and friends.
- Add support for Clp_ValLong.
Correct parsers for new Clp_OptionError return value.
CLP: Improve ambiguous value option.
CLPTest: Update for new CLP negated-only short option behavior.

Also print more information on failures.
Add 'make check' target to run the tests.

Not as good as installing and then running testie tests, but getting
there. Also requires a buildtool update to take elementmap.xml from
CLICKPATH, if CLICKPATH is set.
Some perls can't use \376 as a delimiter any more.

Argh.
Print subtest on testie errors.
Fix tests for some CPPs.