Color code and allow text size change

Reading code on the go via Keybase is a pain

This can be vastly improved by adding the following features, ordered by personal preference

1. Allow text size change
2. Allow landscape mode
3. Color code (even better, color it according to the extension, like GitHub does)

thanks!

No files, tests, or entry points are named. Review the Keybase client area that displays code, then clarify the scope and priority of text sizing, landscape mode, and extension-based color coding; done would require an agreed subset of these features to work.

Written by the indexing model from the issue text.