- cleanup
- code cleanup in EngineImages
- remove unused constants ICON_WIDTH, ICON_HEIGHT
- String#matches? should be case insensitive
- remove UserObect#text_match? and UserObject.text_match? in favor of using String#matches?
- remove unneeded 'return' keywords
- remove unneeded 'if $gui' (gui is always present)
- remove unused last_exception feature
- UserObject code cleanup, reordering
- replace 'throw' with 'raise'
- and => &&
- minor cleanup in Vector3
- remove unused merge_options method
- remove unused files_used methods
- code cleanup
- comment
- factor out Image#call_load_proc_if_needed!
- comment
- Variable and VariableInput code cleanup
- comment
- comment