Ignore case while sorting Library (#2048)

* Ignore case while sorting Library

* Simplify code

As suggested by @arkon

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

@@ -185,7 +185,7 @@ class LibraryPresenter(
 
         val sortFn: (LibraryItem, LibraryItem) -> Int = { i1, i2 ->
             when (sortingMode) {
-                LibrarySort.ALPHA -> i1.manga.title.compareTo(i2.manga.title)
+                LibrarySort.ALPHA -> i1.manga.title.compareTo(i2.manga.title, true)
                 LibrarySort.LAST_READ -> {
                     // Get index of manga, set equal to list if size unknown.
                     val manga1LastRead = lastReadManga[i1.manga.id!!] ?: lastReadManga.size