[BUGFIX] Proper fetching of configured plugins in ControllerActions component
[BUGFIX] Incorrect check for existing class
[FEATURE] Add a reset() method to Providers

Method flushes internal caches completely but can be overridden to perform other actions. Currently not called by our code.
[TASK] Minify clear cache command
[TASK] Remove an unused variable
[BUGFIX] Clear field behavior not respected
[TASK] Refactor ContentProvider to ease test coverage
[TASK] Remove 4.x sheet title support
[BUGFIX] Sheet getFields can return ContainerInterface, should be FieldContainerInterface
[TASK] Let FieldContainerInterface extend ContainerInterface
[TASK] Minify a condition in getMergedConfiguration
[TASK] Do not permanently prevent Providers if registered then unregistered
[TASK] Test coverage of all PR code, increased coverage
[TASK] Let RecursiveArrayUtility cast arguments to array
Merge pull request #413 from NamelessCoder/coverage

[TASK] Quite a few minor tweaks and fixes - and test coverage to 98% of all classes