OpenCDN 0.6.6 released

This OpenCDN release changes the routing algorithm, making it more distributed, and fixes some bugs.
RRDM no more performs loop avoidance, i.e. in SetUp, it no more removes all the TR which are more specific than TR nodes which happens to be also LastHop. Instead, loop avoidance is performed by nodes themselves. In fact, when a lazy TR Node forwards the DoRelay to another TR:
- checks that a LH, with a FP which is more specific than
the FP of the next hop TR, do exist; if not, TR node
becomes labour, and forwards the DoRelay directly to LH
nodes
- if next hop still is a TR, the forwarded LH list is pruned as
well, by retaining only LH nodes whose FootPrint is more
specific than the next hop TR one