Say a shark-toothed smile hello to 0.2-alpha!

This is pretty much a bug fix / quality of life update following the initial alpha release.  Thanks for all the feedback that has helped shape this so far!

CHANGELOG:

• Gameplay: Make player invulnerable during wave exit.
• Gameplay: Improved necromancer hit box.
• Controls: Support AZERTY keyboards.
• Graphics: Make power-up labels a bit bigger.
• Sound: Play tension music when low energy.
• Sound: Remove slight gap at start of main game music.
• Bug fix: Increase 'WAVE X' timer to avoid fish spawning before player in start position.
• Bug fix: Fix 'flash hit' animation for necromancers on spawn.
• Bug fix: Make 'Enemies Left' behaviour consistent between games.
• Bug fix: Tidy up projectiles getting stuck around exit locations in transitions.