0.3.0

Breaking changes

• Take self rather than &mut self for UniqueMmioPointer::split. The old behaviour can be
  achieved by calling reborrow first.
• Take self rather than &self for SharedMmioPointer::split. SharedMmioPointer is Copy so
  this should make no difference in most cases.

Improvements

• Added modify and modify_mut methods to UniqueMmioPointer<ReadWrite<T>> and
  UniqueMmioPointer<ReadPureWrite<T>>.
• Added get_range() methods to UniqueMmioPointer<[T]>, UniqueMmioPointer<[T; LEN]>,
  SharedMmioPointer<[T]>, SharedMmioPointer<[T; LEN]>. These methods return a pointer to the
  subset of elements, specified by a Range.
• Added iter() methods to UniqueMmioPointer<[T]>, UniqueMmioPointer<[T; LEN]>,
  SharedMmioPointer<[T]>, SharedMmioPointer<[T; LEN]>. These methods return an iterator to the
  items of the pointer slices or arrays.