MEG demo update

[JasperVanDenBosch]

• [x] resolves #361
• [x] fixes #362
• [x] fixes #363
• [x] resolves #247
• [x] fix headings

[JasperVanDenBosch]

@HeikoSchuett this is also ready. Main change is the introduction of the timecourse/movie plot from the demo into the toolbox. What do you think?