changes to external URLS for 76
Use a different method to get Stable ID for links to 37 archive (reason being get_predecessors rather than history allows one to get value of old_release using release method).
Add links to all rel 75 IDs found (eg patches and reference)
Update regulatory features track colours.
Use blocks not whiskers for promoter flanks.
Fantom colours and feature priorities.
Heterochromatin colour.
FileHandler moved to Utils
FileSystem moved to Utils
MethodMaker moved to Utils
Merge branch 'master' into feature/tools-dev