Remove ARXOldTimeMenu global
Ignore trailing newlines in OpenGL debug messages
Include entity ID in warning
CMake: Don't fail if GIT_HEAD could not be found
CMake: Add support for packed refs in .git/HEAD
CMake: Use `git` to determine HEAD if available
Fix typo in comment
Rename EntityId members to match code style
Change instance number search to not use entity
Use better variable names
Use better function name and make function static
Use better variable names
Pass instance number at entity construction
Add more EntityManager::getById overloads
Fix broken EntityManager::getById() call
Cache and EntityId in Entity
Make EntityId::string() const
Use EntityId::string() for Entity::idString()

This should give the same result except for special entities like
'player' where we previously erroneously encoded the instance number.
Add EntityId constructor from class path
Use new EntityId constructor in Entity