Add ability to sort library by date added (closes #1287)

(cherry picked from commit 1813dbbf59)

# Conflicts:
#	app/build.gradle
#	app/src/main/java/eu/kanade/tachiyomi/data/database/DbOpenCallback.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/browse/migration/search/SearchPresenter.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/browse/BrowseSourcePresenter.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/library/LibrarySettingsSheet.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/library/LibrarySort.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/manga/chapter/ChaptersPresenter.kt

app/src/main/java/exh/eh/EHentaiUpdateHelper.kt

@@ -9,6 +9,7 @@ import eu.kanade.tachiyomi.data.database.models.MangaCategory
 import exh.metadata.metadata.EHentaiSearchMetadata
 import exh.metadata.metadata.base.getFlatMetadataForManga
 import java.io.File
+import java.util.Date
 import rx.Observable
 import rx.Single
 import uy.kohesive.injekt.injectLazy
@@ -129,8 +130,12 @@ class EHentaiUpdateHelper(context: Context) {
                         }
                     }
 
-                toDiscard.forEach { it.manga.favorite = false }
+                toDiscard.forEach {
+                    it.manga.favorite = false
+                    it.manga.date_added = 0
+                }
                 accepted.manga.favorite = true
+                accepted.manga.date_added = Date().time
 
                 val newAccepted = ChapterChain(accepted.manga, newChapters)
                 val rootsToMutate = toDiscard + newAccepted