OP2/PyOP2 — pull request #158 by kynan (2013-03-14 10:17:41+00:00)
Title: Cache PETSc vectors created from Dats on the Solver

Cache a PETSc vector created from a Dat based on its dimensions and memory address on the Solver object.

[Buildbot pass](http://buildbot-ocean.ese.ic.ac.uk:8080/builders/pyop2-testing/builds/210)