rm bold/italic formatting & switch ["0C"] and ["05"] in geany template

This commit fixes outstanding issues with the base16 implementation for Geany, with an eye on compatibility with RStudio/Ace implementation of the Tomorrow themes. It removes the unnecessary bold/italic formatting in many instances (both dark and light schemes), and switches the ["0C"] and ["05"] base colors in most instances (only the dark theme). All changes were made to improve code readability and general usability of the themes. 

The changes come with the blessing of @RobLoach, the original author of the Geany implementation of base16, and are discussed in this ticket: 
https://github.com/RobLoach/base16-geany/issues/2