NMS-6686: draft of SnmpMonitor documentation
NMS-6686: Examples for SnmpMonitor

- Added example for OID scalar monitor
- Added example for OID table match-all physical drive monitor
- Added example for OID table count for static route entries
Merge pull request #2 from indigo423/patch-2

NMS-6686: Examples for SnmpMonitor
NMS-6686: Corrected the description about how the operating mode selection occur in order to accomodate with
          OpenNMS' strange way of dealing with the "match-all" and "walk" parameters.
NMS-6686: Corrected row spanning in "operating mode selection" table.
NMS-6686: Added table of possible reason-template parameters.
NMS-6686: Implemented most of the suggestions made by reviewers during first review.
Merge pull request #75 from StCyr/cyr-doc-SnmpMonitor

NMS-6686: Create SnmpMonitor documentation