Adds support for SNMPv1 Trap responses

This request adds support for SNMPv1 trap responses per: http://tools.ietf.org/html/rfc1157#page-27 and http://www-01.ibm.com/support/knowledgecenter/SSB23S_1.1.0.10/com.ibm.ztpf-ztpfdf.doc_put.10/gtpc1/pdus.html.

You can now receive trap messages from legacy network devices.
Also minor syntax issues were corrected.