Changeset 1013:f6f6896a4724 in lemon-main for test

Ensure strongly polynomial running time for CycleCanceling? (#436)
The number of iterations performed by Howard's algorithm is limited.
If the limit is reached, a strongly polynomial implementation,
HartmannOrlinMmc? is executed to find a minimum mean cycle.
This iteration limit is typically not reached, thus the combined
method is practically equivalent to Howard's algorithm, while it
also ensures the strongly polynomial time bound.