Locator: Clean up LocatorManager interface

Change-Id: Ib401b6eca8c291526268ccea4d9e7e66f08abe1c
Reviewed-by: David Schulz <david.schulz@digia.com>
Core: Clean up ExternalToolsManager interface

Change-Id: I8ea81de7350bdb0c6243d65596196d615845ffc4
Reviewed-by: David Schulz <david.schulz@digia.com>
ProjectExplorerPlugin: Make settings accessor static

Change-Id: Ic4c78e4d2eefeefe55e2868a7f9db1eca52c3863
Reviewed-by: David Schulz <david.schulz@digia.com>