1) Pass bootstraps and PSK to Add/Get/List/Delete Hash functions
To be used in the SendRequest() function, which has also been
modified to make use of these new params in creating its Node
Fixes regression caused by recent changes that removed hard-coded
bootstrap addresses from common/p2pnode
This is a pre-req for fixing Multi-Tier-Cloud/service-manager#39
2) Call Close() on nodes created by NewNode() when finished with them
Newly introduced method/member introduced in v0.8.1 of common repo
This will also cancel the contexts used in node.Host and node.DHT,
so they shouldn't need to be explicitly closed
3) Pass PSK to sendMemberAddRequest() to use when it creates a new Node
1) Pass bootstraps and PSK to Add/Get/List/Delete Hash functions