* Added source and generated html of manual, and API doc
* setup.py can install the manual (and by extension do can debuild)
* setup.py has (inactive) code for generating the html from the source
but this will break if rtd theme is not available
* A few changes to doc strings to make the autodoc prettier
* Added help shortcut, by default F1 to open the local manual
* Added button to About tab to launch manual
* A couple of additional string to translate related to manual/help
