OP2/PyOP2 — pull request #155 by kynan (2013-03-05 18:28:41+00:00)
Title: Dat.data_ro returns read-only view of the data

Remove all calls to maybe_setflags and leave Dat._data always writable.
We can use needs_halo_update as a dirty flag. It is being set when
accessing Dat.data but not Dat.data_ro.

Previously we had the issue that a Dat argument to a parallel loop
might require a halo update, but was set read-only.