Handle "null" time values for Stacks

The timesince filter expects a date or datetime object, and would fail
when receiving an empty string. Create a new filter that returns the
string value "Never" under these circumstances.

Change-Id: I73f4dbb608fc143c3ac60d753e9e222762579e51
Closes-Bug: #1286959
Remove duplicate colon from Size string

Change-Id: I23354aae9427183bb79e4b51b2c8c29b3519e7ae
Closes-bug: #1298991
Added network's api mocking for the servers_update_addresses method

Change-Id: Idd6ec125ac4c256c1edae445a7bc6a3a70ba4962
Closes-Bug: #1296321
Open Juno development

Bump preversion to 2014.2 to formally open Juno development.
The Icehouse release branch (milestone-proposed) will be cut
from the last commit before this one.

Change-Id: I098875288a7090de75110166b72cc00181ff278c
Merge "Handle "null" time values for Stacks"
Merge "Added network's api mocking for the servers_update_addresses method"
Merge "Open Juno development"
Merge "Remove duplicate colon from Size string"