Make add_vrrp_group more readable

it was hard for us to explain the requirements of the config when adding
a ips to a vrrp group.

This is an attempt to make it more understandable.

Merge pull request #190 from lindycoder/cisco_standby_version

Setup cisco vlans with standby version 2

Support unicast RPF mode for the cisco adapter

Merge pull request #183 from internap/3300_protocol_names

Support correct protocol interface names

Merge pull request #181 from fbouliane/remove-connect-timeout-on-enable

Remove special timeout on enable

Merge pull request #180 from fbouliane/raise-on-enable-failure

Raise when enable fails

Merge pull request #179 from lindycoder/use_page_reader

Use a page reader for every "show" commands on dell powerconnect

Merge pull request #177 from lindycoder/telnet-connect-timeout

Add connect timeout on telnet login hanging

Merge pull request #176 from fbouliane/add-dell-reset-interface-best-…

…effort

Add best-effort reset_interface on dell

Merge pull request #174 from idjaw/master

Freezing lxml version due to errors in build