Add Filter by Completed for library (#941)

* issue 938

added filter by completed manga status

* changed to use existing string
fixed space issue in method in presenter

app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferenceKeys.kt

@@ -87,6 +87,8 @@ object PreferenceKeys {
 
     const val filterUnread = "pref_filter_unread_key"
 
+    const val filterCompleted = "pref_filter_completed_key"
+
     const val librarySortingMode = "library_sorting_mode"
 
     const val automaticUpdates = "automatic_updates"

app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt

@@ -145,6 +145,8 @@ class PreferencesHelper(val context: Context) {
 
     fun filterUnread() = rxPrefs.getBoolean(Keys.filterUnread, false)
 
+    fun filterCompleted() = rxPrefs.getBoolean(Keys.filterCompleted, false)
+
     fun librarySortingMode() = rxPrefs.getInteger(Keys.librarySortingMode, 0)
 
     fun librarySortingAscending() = rxPrefs.getBoolean("library_sorting_ascending", true)