OP2/PyOP2 — pull request #100 by wence- (2012-11-01 15:23:35+00:00)
Title: Matrix plan cache fix

Since the matrix-coloring merge
````python
par_loop(..., mat((map[op.i[0]], map[op.i[1]]), ...), ...)
par_loop(..., mat((map[op.i[0]], map[op.i[1]]), ...), ...)
````
would result in two Plan objects being instantiated. Fix that by computing the matrix subkey correctly.