Fix all demos to import only pi3d.
Change log file to be reconfigurable on the fly.
Lots of minor changes to make sphinx happy.
Minor tweaks to Log.py
merging latest mods from Tom
Merge branch 'develop' of https://github.com/tipam/pi3d into develop
Merge branch 'develop' into release-1.0

to keep latest updates from Tom in the release candidate.