I noticed that the grove LCD screen only has an ASCII/Japanese font table. I need to be able to display accented characters
looking at the data sheet the screen supports up to 8 custom CGRAM characters. I added an API to set those CGRAM characters
as well as a map of common latin 1 characters + emoticons
The refactoring focuses on 2 aspects:
* go lint conventions with documentation
* avoid naked returns and don't instantiate returned values in the signature unless really necessary