[Azoth Modnok] Make QImage a known type.
[Rosenthal] Checker::LearnWord().
[Interfaces] ISpellChecker::LearnWord().
[WKPlugins] Added SpellcheckerExt.
[WKPlugins] Use normal LC_PLUGIN_METADATA.
[WKPlugins] Build spellcheckext.cpp.
[WKPlugins] Added settings.
[WKPlugins] Autocorrect made optional.
[WKPlugins] Expose spellchecker extension.