[R] Wrap MemoryMappedFile class

[asfimport]

This will support zero-copy shared memory IPC. This first requires being able to handle arrow::Buffer objects in R.

Reporter: Wes McKinney / @wesm
Assignee: Romain Francois / @romainfrancois

_{Note: This issue was originally created as ARROW-3450. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Resolved in b027f5a (PR title had a typo)