Shell assignment operator in BSD make != is ported to GNU make in
version 4.0, so 3.x doesn't work. I choose to drop BSD make support as
installing GNU make on *BSD systems is easier than installing newer GNU
'make lazy-extractors' creates the youtube_dl/extractor/lazy_extractors.py (imported by youtube_dl/extractor/__init__.py), which contains simplified classes that only have the 'suitable' class method and that load the appropiate class with the '__new__' method when a instance is created.
Add auto-updating of youtube-dl version in ISSUE_TEMPLATE
Move parts of template text and adopt makefile to new format
Moved the 'kind-of-issue' section and rephrased a bit
Rephrased and moved Example URL section upwards
Moved ISSUE_TEMPLATE inside .github folder.
Update makefile to match new folderstructure