Allow custom SSO cookie name to be configured

Crowd allows the use of custom SSO cookie names, to enable segmentation between application zones. The default is "cookie.token_key" but it can be overiden in configuration.

From the crowd wiki documentation: (http://confluence.atlassian.com/display/CROWD/The+crowd.properties+File)
(setting) cookie.tokenkey
(descirption) When using Crowd for single sign-on (SSO), you can specify the SSO cookie name for each application. Under the standard configuration, Crowd will use a single, default cookie name for all Crowd-connected applications. You can override the default with your own cookie name.
As well as allowing you to define the SSO cookie name, this feature also allows you to divide your applications into different SSO groups. For example, you might use one SSO token for your public websites and another for your internal websites.
(default value) crowd.token_key

Please enable setting a custom SSO cookie name so that we can use the SSO features.