- support pinned memory on the host side (active on default)
  - support managed memory
  - support zero copy
  - replace transfers with prefetch instructions in case of managed memory
  - eliminate transfers when zero copy is used

prepare memory management for GPU communication buffers

-> identifier denotes a combination of name and level, everything else is a name
-> {field, domain, etc.}Name denotes the name of a linked object
-> {field, domain, etc.} denotes a reference to a linked object

- new trait ir SpecialExpandable to mark non-final nodes
- one default prettyprinter for all expandable and special expandable nodes
- use Knowledge dimensions where applicable
- shorten some names (mostly omit 'Expression')