Add an appendix

For the inclusion of js libraries or general html elements outside the scope
of flowtime, we can pass a performatted html string.

Signed-off-by: Christoph Höger <christoph.hoeger@tu-berlin.de>

Output jade error messages

This saves you alot of time, when you are on a plane and cannot
figure out about which syntax error jade complains this time...

Signed-off-by: Christoph Höger <christoph.hoeger@tu-berlin.de>

Close outermost div and move appendix behind it

Signed-off-by: Christoph Höger <christoph.hoeger@tu-berlin.de>
Implement Suggestions from @xogeny

Signed-off-by: Christoph Höger <christoph.hoeger@tu-berlin.de>
Merge pull request #28 from choeger/master

A few simple fixes and enhancements