Minor code improvements

Doesn't affect the gameplay.

Minor code changes

The compiled .hex files are actually unchanged, but the info.json in the .arduboy file has been updated regardless.

Fix compilation error

Fixes a bug in the source code that was preventing compilation.

The big theme update

• Upgraded theme easter egg into proper theme system complete with backgrounds
• Overhauled save system to be bidirectionally compatible
• Uploaded graphics under CC BY-NC-SA
• Removed dynamic allocation
• Changed ES-ES to ES-CL
• Added more credits
• Slightly reorganised stats screen
• Shifted all code into subdirectory

Reformat stat screen

Minor reformat of stat screen layout.

Fix Linux compilation

This fixes the issue that was preventing the code from compiling on Linux.

Bug fixes and German localisation

• Added DE-DE (courtesy of @Nicole_Birgel)
• Fix the save check dialogue not appearing
• Fix saving not being disabled when selecting 'no' from the save check dialogue

Fix some mistakes

• Fixed a typo in FR-FR localisation (pointed out by @vampirics)
• Added the missing .ino file
• Add an .arduboy file to the release

Finally

Initial release.

Languages supported:

• EN-GB (courtesy of @Pharap)
• FR-FR (courtesy of @vampirics)
• ES-ES (courtesy of @eried)
• EN-AU (courtesy of @filmote)
• EN-LCY (courtesy of Phil Mitchell, Mick Carter and The Hitcher)