Consider improvements to demo framework

[Martin Sandve Alnæs]

Demos in dolfin needs to fulfil a range of requirements. Consider if improvements can be made to our current framework.

The main categories of requirements are:

• Automatically testable as part of regression test suite.
• Well explained and documented (the undocumented/ folder drops this requirement).
• Automated inclusion of code and its documentation on webpage.
• Python and C++ version.
• Code should be easy to copy and use as basis for user experimentation.

[Anders Logg (Chalmers)]

Removing milestone: 1.8 (automated comment)