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
Improving navigation

[Feature description]

When in a workspace:
* brand product at top left screen is the workspace name
* navigation to workspace components use workspaces links

Navigation is localized.

[L10n]

Home, Help

Help topics aren't localized, as help isn't currently available
in other languages than English.