Update README.md
Update README.md
Refactor source files to use 'using namepsace gs'.
Remove Skin class.
Put CShapes class inside gs namespace.
Tidy up #includes.
Rename IEvent to Event.
Fix indentation to single tab.
Refactor headers to use gs convention:
- hpp for headers with no corresponding cpp
- h for headers with an associated cpp
Documented event classes.
Merge branch 'develop' into f_input