Only send the hsts header if the scheme of the call is https
- Added unit tests to test https only functionality.
- Added two more unit tests to test the overwrite branch in the Callback Action.
Added space before semicolon when including sub domains
Merge pull request #1 from estei/only-send-on-https

Only send the hsts header if the scheme of the call is https
Merge pull request #2 from estei/field-syntax-missing-space

Added space before semicolon when including sub domains