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

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt

@@ -218,6 +218,7 @@ class LibraryPresenter(
                         ?: latestChapterManga.size
                     manga1latestChapter.compareTo(manga2latestChapter)
                 }
+                LibrarySort.DATE_ADDED -> i2.manga.date_added.compareTo(i1.manga.date_added)
                 else -> throw Exception("Unknown sorting mode")
             }
         }

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibrarySettingsSheet.kt

@@ -111,10 +111,11 @@ class LibrarySettingsSheet(
             private val lastChecked = Item.MultiSort(R.string.action_sort_last_checked, this)
             private val unread = Item.MultiSort(R.string.action_filter_unread, this)
             private val latestChapter = Item.MultiSort(R.string.action_sort_latest_chapter, this)
+            private val dateAdded = Item.MultiSort(R.string.action_sort_date_added, this)
 
             override val header = null
             override val items =
-                listOf(alphabetically, lastRead, lastChecked, unread, total, latestChapter)
+                listOf(alphabetically, lastRead, lastChecked, unread, total, latestChapter, dateAdded)
             override val footer = null
 
             override fun initModels() {
@@ -133,9 +134,12 @@ class LibrarySettingsSheet(
                     if (sorting == LibrarySort.LAST_CHECKED) order else Item.MultiSort.SORT_NONE
                 unread.state =
                     if (sorting == LibrarySort.UNREAD) order else Item.MultiSort.SORT_NONE
-                total.state = if (sorting == LibrarySort.TOTAL) order else Item.MultiSort.SORT_NONE
+                total.state =
+                    if (sorting == LibrarySort.TOTAL) order else Item.MultiSort.SORT_NONE
                 latestChapter.state =
                     if (sorting == LibrarySort.LATEST_CHAPTER) order else Item.MultiSort.SORT_NONE
+                dateAdded.state =
+                    if (sorting == LibrarySort.DATE_ADDED) order else Item.MultiSort.SORT_NONE
             }
 
             override fun onItemClicked(item: Item) {
@@ -161,6 +165,7 @@ class LibrarySettingsSheet(
                         unread -> LibrarySort.UNREAD
                         total -> LibrarySort.TOTAL
                         latestChapter -> LibrarySort.LATEST_CHAPTER
+                        dateAdded -> LibrarySort.DATE_ADDED
                         else -> throw Exception("Unknown sorting")
                     }
                 )

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibrarySort.kt

@@ -8,6 +8,7 @@ object LibrarySort {
     const val UNREAD = 3
     const val TOTAL = 4
     const val LATEST_CHAPTER = 6
+    const val DATE_ADDED = 7
 
     @Deprecated("Removed in favor of searching by source")
     const val SOURCE = 5