Dump capability registers on unaligned CLD/CSD to aid debugging.
Actually copy the packet to the space we allocated.
Don't set a length on the capability in sandbox mode.

If the offset is non-zero the new bounds are wrong.

These probably shouldn't exist at all in sandbox mode, but tcpdump
currently uses them to leave them alone for now.
Add a simple CHERI_PRINT_PTR macro to print some information about a
capability.
Make cheri_tcpdump sandbox colors optional.