Allow #AARRGGBB color definitions to pass HexValidation

In IE filter definitions, #AARRGGBB is the way to specifiy a color
with some transparency. See:
http://msdn.microsoft.com/en-us/library/ms532879%28v=vs.85%29.aspx

Change-Id: I0acdf5607f8fbf2545402fd0d044c0ef7f3c5cf6
Reviewed-on: http://gerrit.causes.com/41621
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>
Update changelog with HexValidation fix

Change-Id: Ie9199d82d4c39a2984773585972c3ee613c0b7e3
Reviewed-on: http://gerrit.causes.com/41622
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>