Settings-class currently enables style checking via dedicated
boolean attribute. All other CLI's enable-options are handled
through the enable-list. This commit moves style-check enabling
to use the enable-list.
Main advantage is the consistency how options are handled/stored
in the Settings class. Which also unifies using them for the other
code. You need to enable certain type of checks? Use the
addEnabled()-method. You want to check if certain type of checks
are enabled? Use the isEnabled()-method.