CodeCov Extended

I'm colourblind and CodeCov's new UI made it very hard to view coverage on a PR, so I've created this extension to help with that. There are few bits and pieces to begin with, hopefully I'll be able to extend it when I get the time. Or CodeCov will fix their UI :) - Highlights covered, uncovered and partially covered lines with colours customisable by the user - Automatically 'expands' up all files which have uncovered/partially covered lines - Displays the total of uncovered/partially covered lines in a sidebar - Links to each uncovered/partially covered line in a sidebar