Fix hierarchy of headings.

'Title' is inserted as <h1>, so all sub-headings
should be <h2> (or deeper). Change '#' to '##' in
markdown accordingly, where appropriate.

Signed-off-by: Thomas Hochstein <thh@inter.net>
Codebreaker-Workshops
Merge pull request #9 from th-h/thh-fixheadings

Fix hierarchy of headings.
Fix time
Update Twitter
Update Twitter
Folienreferenz
Audio link
Update Twitter
Update Planet
Update Twitter
Blogartikel Rückblick Smartphones Schule
EH-Presselink
Update Twitter
Update Twitter
Update Twitter
Fix date and add some 's'
Neuer Blogartikel Smartphone-Messenger
Update Planet
Remove Easterhegg announcement