- made public headers compilable individually
- easier access to settings section delegates
- removed module singleton accessor
- moved non-trivial definitions into cpp files
- code & documentation cleanup
#UpgradeNotes:
- instead of ISettingsModule::Get() use FModuleManager::GetModulePtr<ISettingsModule>("Settings")
- instead of using FSettingsSectionDelegates assign delegates directly through the new ISettingsSection methods
[CL 2340711 by Max Preussner in Main branch]
- removed dummy UClasses (no longer needed)
- removed file header comments (not used)
- removed duplicated function documentation in cpp files
- documentation cleanup, punctuation, spelling etc.
- pragma once include guards (now work on all platforms)
- relative public includes (are auto-discovered by UBT)
- fixed too many/too few line breaks
- deleted empty files
- missing override
- NULL to nullptr
[CL 2305058 by Max Preussner in Main branch]
