My own pass on cleanups

* Updates the component manifest for the forked version
* Bumps the component version to `4.0.0-dev`
* First pass on cleanup of `LocaliseHelper` to include:
    * Code style with doc blocks to better identify methods purposes
    * Removes `LocaliseHelper::getActions()` in favor of `JHelperContent::getActions()`
    * Optimizes the language loading code based on the default loading en-GB handling in core
    * Drops code checking PHP versions unsupported by 3.3
    * Use less of the Filesystem package and more native PHP where appropriate