Utility: minor refactoring.
Utility: deinlined internal ConfigurationGroup constructor.
Utility: minor cleanup.
Utility: don't overwrite file with results of previous tests.
Utility: more robust ConfigurationGroup copying, standalone ConfGroup.

Fixed passing reference to enclosing Configuration in copy constructor,
added some assertions, allow for creating and using standalone
ConfigurationGroup (not belonging to any Configuration instance).
Utility: minor cleanup.
Utility: move construction and assignment for Configuration[Group].

Also removed done/wontfix TODOs.
UseCorrade.cmake: treat resource configuration file as dependency too.

Triggers rebuild when resource list is changed.
Utility: wrap configuration value in "" only if really needed.

Wrapping only if it has leading/trailing whitespaces. What a horror,
making this change didn't break _any_ unit tests, so this wasn't tested
at all. WTF. Updated whitespaces test to test this.