1736 - Staircase

Hotfix release.

• #88: Fixes that tapping a specific location on the mobile rollout menu would cause a crash. Thank you @pancelor for contributing to a fix!
• Related to #31: Fixes that a message directly in-between levels (without newlines) would cause the level after it to fail loading.

There have been a number of changes behind the hood, mostly related to setting up the test suite.