Fix missing absolute import declarations

src/octoprint/__init__.py

@@ -1,4 +1,6 @@
 #!/usr/bin/env python
+from __future__ import absolute_import
+
 import sys
 from octoprint.daemon import Daemon
 from octoprint.server import Server

src/octoprint/timelapse.py

@@ -1,4 +1,5 @@
 # coding=utf-8
+from __future__ import absolute_import
 
 __author__ = "Gina Häußge <osd@foosel.net>"
 __license__ = 'GNU Affero General Public License http://www.gnu.org/licenses/agpl.html'

src/octoprint/util/__init__.py

@@ -1,4 +1,6 @@
 # coding=utf-8
+from __future__ import absolute_import
+
 """
 This module bundles commonly used utility methods or helper classes that are used in multiple places withing
 OctoPrint's source code.