Add two create functions, fix en_us time and long time.

Add new create functions dateFromFieldsRecord, timeFromFieldsRecord.
Thanks to @synalysis for fix to en_us time and long time config.

Update doc only for Create module.

Suggested by @akrejczinger thank you.

Add Norwegian, Add Spanish

Thanks to @sindreij for Norwegian and a fix for something in Swedish
Thanks to @aherranz for Spanish

Fix Duration.diff possible negative values for a positive difference

Thanks to @ikr for two useful test cases demonstrating failure.

Fix a doc typo, and some empty tests suites in some time zones.

Thanks to @ikr for the typo fix and for pointing out elm-test reports fails on empty test suites.

Documentation update only.

Thanks to @ryan-senn for his fixes for two documentation types.

I have also updated the documentation for Period and Duration to try and make it clearer, fixing a problem in an example cause in Duration that has caused confusion.

With this work I have realised that when i used the concepts of Period and Duration from nodatime that I managed to swap them around in elm-date-extra. My apologies if I have confused anyone it was not intentional.

I have not yet decided if I should swap the the Period and Duration module functionality over so they align with nodatime as yet.

Fixed export of TwelveHourClock and I_default.

Thanks to @BrianHicks for spotting this and the pull request.

Update French, Add additionat Format fields.

• French now shows hours in 24 hour format thanks to @FabienHenon for pointing it out.
• Added the result of Utils.isoWeek as format stirng options %Gm %V, %-V, %u

Fixed doc

Thanks to @fdbeirao for spotting and fixing DocFormat.md documentation for 2 digit year.

Improved Russian, Add Swedish.

Thanks to @NeverwinterMoon for his contribution.