Documentation generation fails due to python include path errors

[JohnVidler]

The documentation generation function of build.py includes a bunch of utility libraries on the utils/python subpath, but as these are outside the python include path, they fail to resolve and halt the script.

These all need to be moved to either:

• Dynamic includes via importlib with the paths corrected
• An updated system path at runtime to match the inner script root

[JohnVidler]

Some documentation can now be built via ./build.py --bootstrap --makedocs although this is very experimental while I get the supporting files sorted.