Fix unintentional humor.
Fit the text in 3 lines.
Fix compilation issue with abs() on windows.
Update compilation instructions.
Refactoring pixel scaling.
Remove trailing whitespace.
Move the Scale2x code to a separate class.
Add the hq4x pixel filter (#331).
Remove empty line.
Tabs are evil.
Fix indentation.
Fix teletransporter activated while coming back from falling (fix #346).
Fix teletransporter activated while coming back from falling (fix #346).
on_key_pressed() and on_character_pressed() are independent (fix #344).
Fix a crash when changing the hero state in block:on_moved() (fix #340).
Fix a crash when changing the hero state in block:on_moved() (fix #340).
Add a boolean to indicate whether an object exists in the Lua (#347).

The next step will be to test this boolean in all events.
Force assertion errors to show an error message.
Add a function indicating whether an object was exported to Lua (#347).
Rename is_exported_to_lua() to is_known_to_lua().