build_examples supports cleaning examples and intelligently will detect new examples.
SUGGESTION: When merging into dev, require
```
build_examples.py clean
```
and then only build when merging into master branch
There are hard copies of the graphviz and pyyaml dependencies included
in the repo. Remove these.
Sort out installation and dependency handling by writing a functional
setup.py script. Rename top level documentation. Refactor wireviz.py
slightly to allow it to run as an installed script.
# Conflicts:
# src/batch.py
# src/wireviz/batch.py
# src/wireviz/build_examples.py
