Mock remote issues

[stefpiatek]

• Not quite convinced that I've got the best place for processing raw issue data into design stages so any thoughts there would be good
• Moved the remote repository files into their own modules and made use of abstract base classes so we have to implement properties
• in tests, can read from filesystem, imagine during testing we may need to pass in a temporary test directory, which we can setup there. Using the frontmatter in markdown to keep all the values that we'd get some the github object
• Next steps might be persisting the json data to a file, then maybe working on the freeze to be able to find changes to ignore or increment the version?

[tim-band]

Just one simple change