Shits broke. Checking master
Get & set for net-snmp repl implemented
net-snmp2 util implemented

 - get, get_next, get_bulk, walk, set supported
 - Multiple sessions supported via `manage` & `close`
 - MIB operations supported with `describe` & `translate`

All operations seem to agree with output from snmp[operation], though not
alwasy with MIBBrowser. (MIBBrowser seems to accept responses from walks
that are not part of the subtree requested for walking.)

Some trap unit tests are failing. Need to verify behavior on master, and
possibly fix. Though, no trap logic should have been affected.
Sessions in net-snmp2 repl may be closed by index

  - Also updated Sessions constructor to take port number in peername
    such that the following should be equivalent...

    + Session.open(peername: 'localhost:161')
    + Session.open(peername: 'localhost', port: 161)
get_node throws if given an invalid MIB variable name
Finished initial implementation of net-snmp2 utility