Integrate optional captcha service for the contact form.
Fixing travis configuration issue.
Pin wsgi_intercept in travis configuration.
Added option to set the theme of the recaptcha widget.
Update german translation.
Pin kotti to latest stable release.
Public and private key are not required, it's possible to use the form
without the captcha.
The captcha setting defaults to False.
Missing import statement.
Refactore widget template.
Update german translations.
Merge pull request #10 from j23d/captcha-integration

Captcha integration, fixes #3