SettingHelper: don't set callbacks in '->getDefaults()', making this more generally usable.  Instead, allow passing a callback that can do the rendering.
settinghelper: finished unfinished comment about `set()` method
SettingsHelper: `buildSettingsArray()` method now used to merge arrays of settings and modify with callables.  `getBaseDefaults()` now just returns an array
settinghelper: removed renderer stuff, as it is no longer used by class directly and can be accessed differently from callbacks
settinghelper:buildSettingsArray(): allow importing of a json file