demos, logging, build fixes

[casperdcl]

• replace Cnt['VERBOSE'] with pythonic logging
• include Jupyter DEMO.ipynb
• fix some import errors
• allow non-interactive installation
  • allow setting HMUDIR env var
• fix numpy include headers location (for e.g. dist-package rather than site-package install)
• lots of minor tweaks and improvements
  • whitespace fixes
  • tqdm progressbar
  • README badges & installation instructions