[TASK] Use internal getExtensionKey method in postprocessing FlexForm structure
[BUGFIX] Fix retrieval and merging of variables in Previews
[BUGFIX] Prevent double registration of ConfigurationProviders
[TASK] Allow passing template variables to use when reading stored variable
[TASK] Set a fallback extension key for Flux controllers

This key can be used to fetch fallback template paths among other things.
Merge pull request #69 from NamelessCoder/postfixing

[TASK] Post-fixing after service unification