Update snmp.py

Change for SNMPv3 to work correctly
(fix) Handling networks with gereric IDs instead of names.
Fixed 'Bulk edit' button on 'Ventures' and 'Racks' views.
(+ some cosmetic changes)
Updated changelog part 2.
Merge pull request #882 from xor-xor/changes

Updated changelog part 2.
Merge pull request #879 from xor-xor/fix_1636_2

(fix) Handling networks with gereric IDs instead of names.
Renamed to rc7
Bumped version to 2.0.0-rc7
Updated copyrights in LICENSE.
Merge pull request #883 from xor-xor/dates

Updated copyrights in LICENSE.
Merge pull request #881 from xor-xor/fix_1689

Fixed 'Bulk edit' button on 'Ventures' and 'Racks' views.
Update CHANGES.rst
Fixed formatting
Merge branch 'develop' of https://github.com/allegro/ralph into release/2.0.0-rc7
Model change
Migrations (untested)
Fixed precedence
JiraChanges are visible for the new schema
walk function
Changes are propagated down