Feature request: case insensitive search

[Arc676]

Since the xkcd font looks exactly the same in upper and lowercase, it would make sense if the application doesn’t differentiate between them. The search function should be case insensitive to match this but also for simplicity, as text could appear at the beginning of a sentence and thus be capitalized (this shouldn’t prevent a comic from being shown as a search result). As a simple example, searching “Planck” yields 485: Depth but searching it in lowercase yields no results.