* rename local variables in main file
* additional renaming of functions and variables
* Rename main file functions
* Rename functions and variables in canvas.py
* Rename functions and locals for remaining files
* Rename non-Qt derived class' members
* Rename members of Qt-derived classes
* Fix paint label issue
* adds createMl reader & writer class
* adds getFormatMeta function to support more than two save_format
* adds CreateML read & write support
* adds format CreateML icon
* fixes negative height/width
* removes type hints
* fixes coordinate calculation
* adds unit test
* removes typehint
Use lxml to pretty the xml instead of minidom because minido does not support unicode
Save xml with unicode
Add tests dir to collect more images for unit tests in the future