Now available on Google Play. Fix a crash in Net

Run in Android environments where puzzles make sense: phones, tablets, Chromebooks, maybe TVs, not watches or cars. Provide the same puzzle collection that the upstream project provides for other platforms. Provide appropriate controls for Android environments, e.g. on-screen buttons and the use of long-press instead of right-click. Provide appropriate display adjustments for mobile use-cases, e.g. night mode, and minor changes to the recommended sizes of puzzles. Run completely offline, including the documentation, and with minimum required permissions. Follow Android conventions: implicit saving of games in progress, standard settings screen with immediate apply, etc. Make it easy to exchange saved puzzle states with other users and other platforms. Potential/experimental goals, that could exist on Android before potentially being included upstream later: Accessibility improvements relative to upstream. Translate the Puzzles into more languages: first fix issue #1 properly to allow translating strings that come from C, which is most of them. I don't yet know how to fix that, and I don't recommend starting work on any translations until it's fixed. Make it easier to have multiple states of the same game in progress, without having to manage files.