Instead of having an ID allocator per object class use one global allocator for
all. Thereby artificial limitations for the different object types are
superfluent. Moreover, replace the base-hw specific id allocator implementation
with the generic Bit_allocator, which is also memory saving.
Ref #1443
In order to match the I/O APIC configuration, a request for user timer
IRQ 0 is remapped to vector 50 (Board::TIMER_VECTOR_USER), all other
requests are transposed by adding the vector offset 48
(Board::VECTOR_REMAP_BASE).
This patch contains the initial code needed to build and bootstrap the
base-hw kernel on x86 64-bit platforms. It gets stuck earlier
because the binary contains 64-bit instructions, but it is started in
32-bit mode. The initial setup of page tables and switch to long mode is
still missing from the crt0 code.