Make make docs work.

This means you can run:
$ make html_docs
or
$ make docs
to generate the html (+qch) files.

The docs get generated in qtbase/doc/enginio-qt.
Alternatively run qdoc on doc/enginio-qt.qdocconf directly.
Use the Qt look for the docs, otherwise they look just broken.
Documentation update
Mark old docs as internal for now
Add docs, getting started C++
Add QML docs
Merge pull request #59 from gladhorn/documentation

Documentation