Removed the old security system.

Signed-off-by: Wolf480pl <wolf480@interia.pl>
Added CommonPolicy.CommonPermissionCollection

Signed-off-by: Wolf480pl <wolf480@interia.pl>
Added YamlConfiguration to CommonPolicy

Signed-off-by: Wolf480pl <wolf480@interia.pl>
Added BrowserPermission
Added Client.openBrowser(URI)

Signed-off-by: Wolf480pl <wolf480@interia.pl>
Added required and optional clearances to PluginDescriptionFile.
Don't load the plugin at all, if the required clearances are not
granted.
Started adding default plugin permissions.
Added ClassLoaderFactory
Added OptOutPermission, it will bee needed for (Almost)AllClearance
Added one more permission to default plugin permissions.
Improved CommonPolicy.getPermissions()
Added doPrivileged in CommonPolicy to avoid StackOverflow.