Download manager rewrite (#535)

* Saving to SD working

* Rename imagePath to uri

* Handle android < 21

* Minor changes

* Separate downloader from the manager. Optimize folder lookups

* Persist downloads across restarts

* Fix for #511

* Updated ReactiveNetwork. Add some documentation

* More documentation and minor fixes

* Handle persistent notifications. Other minor changes

* Improve downloader and add documentation

* Rename pageNumber to index in Page class

* Remove unused methods

* Use chop method

* Make sure dest dir is created

* Reset downloads dir preference

* Use invalidate options menu in download fragment and fix wrong condition

* Fix empty download queue after application restart

* Use addAll method in download queue to avoid too many notifications

* Inform download manager changes

app/src/main/java/eu/kanade/tachiyomi/data/database/queries/ChapterQueries.kt

@@ -33,6 +33,15 @@ interface ChapterQueries : DbProvider {
             .withGetResolver(MangaChapterGetResolver.INSTANCE)
             .prepare()
 
+    fun getChapter(id: Long) = db.get()
+            .`object`(Chapter::class.java)
+            .withQuery(Query.builder()
+                    .table(ChapterTable.TABLE)
+                    .where("${ChapterTable.COL_ID} = ?")
+                    .whereArgs(id)
+                    .build())
+            .prepare()
+
     fun insertChapter(chapter: Chapter) = db.put().`object`(chapter).prepare()
 
     fun insertChapters(chapters: List<Chapter>) = db.put().objects(chapters).prepare()