Move the cmake check for ObjectiveC compiler to an own
file. Tweak the output a bit.

Rename 'silverbox' to 'box', across the board.
Delete the remnants of the old build system
(scripts/rules.mk and scripts/config-def.mk).

Do not touch client/perl for now, since it's maintained
elsewhere.

Add the simplest CPack configuration for
'make package' and 'make package_source'
targets.
Add an empty snapshot to revision control
to use in 'make package' and thus
spare the user from the need to do
--init-storage.
Modify args.test to accept a bare
(no git version) version number, and thus
ensure the user from a yet another call before
he/she can start work/play around.