To give the platform developer more freedom in how the Native_capability
class is internally implemented (e.g. turning it into a smart-pointer),
this patch removes the memcpy operation, when transfering the parent-capability
to a new process from the generic code, and let the implementation of the
platform-specific Native_capability decide how the transfer has to be done.
Please refer to issue #144.
The startup procedure of forked processes differs from Genode's
normal process creation by omitting all steps related to ELF loading
and the start of the main thread. To let the process lib support this
distinction, an invalid ELF-binary capability is handled as valid
argument now.