Feature: workspaces selector

[ Feature description ]

• When an user logged in to the Obsidian homepage instead of a workspace homepage, the following behavior happens:
  
  (1) If he has access to exactly one workspace, we automatically switch to this template (without URL redirect). We show the home_workspace.tpl view (the workspace dashboard).
  
  (2) If he has access to several workspaces, a selection has to be made, we show the home_pickworkspace.tpl view.
  
  (3) If he hasn't access to any workspace, we show the home_noworkspace.tpl view.

• When an user go to the /<workspace code> URL, we show the view home_workspace.tpl.

[ Libraries update ]

• New method: Workspace::fromCode($code) Loads the specified workspace from code

[ Views ]

• New view: home_workspace.tpl
• New view: home_pickworkspace.tpl
• New view: home_noworkspace.tpl
• Deleted view: home.tpl

[ L10n ]

• PickWorkspace, PickWorkspaceCallForAction

[ Design ]

• Import block grid CSS code from Foundation 5