Still working things out in C++

Now using a Qt Creator project file so we can use Qt Creator as our text
editor. Got rid of obsolete files. Still trying to figure out what kind
of data each class should be responsible for. Trying to avoid getters
and setters as well as the whole "C with classes" thing. Trying to make
a really good C++ representation of our little protocol here.
Added a gitignore

Ignore Qt project user files.