Update code to get rid of warning messages

A GTK+-3 widget to display data

Brought to you by: baccala, electronjunkie, felipo, flatmax, rbock

Milestone: Next Release (example)

Status: open

Owner: nobody

Labels: None

Priority: 5

Updated: 2021-04-18

Created: 2019-03-23

Private: No

Some GTK/GDK functions are deprecated, it would be good to substitute them with newer recommended ones.

There are also warnings about unused variables, please comment them out or completely remove them.

In some cases, only indentation problems arise pedantic warnings, please indent all the code using the /scripts/indent.sh