[ANN] netsnmp 0.4.0 released

netsnmp 0.4.0 has been released.

This gem provides:

   - Implementation in ruby of the SNMP Protocol for v3, v2c and v1 (most
   notable the rfc3414 and 3826).
   - Client/Manager API with simple interface for get, genext, set and walk.
   - Support for concurrency and evented I/O.
   - Ruby >= 2.1 support (modern)
   - Pure Ruby (no FFI)
   - Easy PDU debugging

### 0.4.0

#### Features

* New debugging logs: `NETSNMP::Client.new(..., debug: $stderr,
debug_level: 2)` (can also be activated with envvar, i.e.

#### Improvements

* octet strings are now returned in the original encoding; Binary strings
are now returned as an "hex-string", which will be a normal string, but
it'll print in hexa format, a la netsnmp.

#### Bugfixes

* incoming v3 message security level is now used to decide whether to
decrypt/authorize (it was taking the send security level into account);
* reacting to incoming REPORT pdu with `IdNotInTimeWindow` OID by updating
the time and replay request PDU (something common to Cisco Routers);
* Fiterling out unused bits from V3 message flags;