vm-memory-v0.2.0

Added

• [#76]: Added get_slice and
  as_volatile_slice to GuestMemoryRegion.
• [#82]: Added Clone bound
  for GuestAddressSpace::T, the return value of GuestAddressSpace::memory().
• [#88]: Added as_bytes for
  ByteValued which can be used for reading into POD structures from
  raw bytes.