Cleanup and fix a few compiler warnings

app/src/main/java/exh/md/handlers/PageHandler.kt

@@ -5,6 +5,7 @@ import eu.kanade.tachiyomi.network.asObservableSuccess
 import eu.kanade.tachiyomi.source.model.Page
 import eu.kanade.tachiyomi.source.model.SChapter
 import exh.md.utils.MdUtil
+import kotlinx.serialization.ExperimentalSerializationApi
 import okhttp3.CacheControl
 import okhttp3.Headers
 import okhttp3.OkHttpClient
@@ -14,6 +15,7 @@ import rx.Observable
 // Unused, kept for reference todo
 class PageHandler(val client: OkHttpClient, val headers: Headers, private val imageServer: String, val dataSaver: String?) {
 
+    @ExperimentalSerializationApi
     fun fetchPageList(chapter: SChapter): Observable<List<Page>> {
         if (chapter.scanlator.equals("MangaPlus")) {
             return client.newCall(pageListRequest(chapter))