seoul: split vancouver run script into smaller ones

Issue #806
seoul: implement heap_free

Avoids the message

cxx: operator delete (void *) called - not implemented. A working implementation is available in the 'stdcxx' library

during a " new ..." which causes exceptions. Happens for seoul in disk.cc

Issue #806
seoul: catch exception during block session creation

Leads to invalid utcb state and later on to invalid vCPU state.

Issue #806
seoul: use utcb guard

Forgetting to restore the old utcb content results in hard to debug bugs.
Save only the amount of word items which are actually on the UTCB.

Issue #806
seoul: fix console output in vga text mode

Issue #806
seoul: fix disc boot

Additionally use the block session interface asynchronously to let the VM
continue execution.

Fixes #806