Fix the sample config

IpInfoDB is no longer used, "host" option removed since it is now set
in the .env file, and YAML doesn't support "nil"; it converts it into
a string.
Add the seed task to the readme
Use hardware acceleration on the aircraft animation

Ref #394
Update jquery.scrollTo to 1.4.7

Fixes #375
Add the supply and demand section to the tour

Ref #366
Added dutch translation
Fix tour appearing over EOL browser message

Closes #411