file reorganisation #1

Reorganize the file structure by putting actual program to "src" folder, testcases to "tests" and a separate folder called "about"/"readme"/"general", where we would keep proper, working copy of the current program, pdf files, anything which isn't code. README.md and LICENCE stay in root.
We have to put a special file to src, called init.py so that module is initialised properly.
and to make things ultimately pretty, I'd love global_values.py to go away. And the imports should work:
import src
circle = src.Circle()
circles = src.Circles()
etc.