Add an ini writer that respects the file structure and the comments that may be
already present in the config file. Move Application/Config.php into
Config/Config.php.
refs #4352
Add a function to create diffs between two object, add a
FileEditor to edit files line-by-line and add the class PropertyDiff to
describe a single property change.
refs #4352
Jannis Moßhammer
Matthias Jentsch