refs #14 - evs improvements for big groups and packetloss

EVS:
* Improvements in membership protocol to handle better big number
  of concurrently joining nodes
* Reduced default install timeout to half of inactive timeout to restart
  gather phase faster if consensus is not reached
* Made membership protocol to try harder to keep majority of nodes in group
  in case install timeout expires
* Implemented isolation mode so that node can isolate itself from other
  group for a while if membership protocol does not converge fast enough
* Fixed flaw in user message loss checking, now also delayed messages are
  detected
* Improved message recovery so that any node can retransmit user message
  in behalf of message originator if gap message originator requests so
* Compactified UUID string representation and evs state dumps

Other:
* Protocol level support for fencing
* Extended gmcast relaying to last peer_timeout_ after full connectivity
  has been established