SaveLoad module for pixel_canvas colored version

* main pixel_canvas file moved to a separate folder in the repo
* .gitignore file added for the repo. 
   Just avoiding .pyc files and other unwanted autogenerated files from being pushed to the repo
* Main addition is saveload.py and PyGameButton.py 
* rest of the files are __init__.py for various folder structure like /plugins, /libs
* One font file in /libs
* saved to and loaded from a default file save.pc