Updated examples and SCH files to UUIDv4

[braeckel]

All examples now have every gml:id set to a UUIDv4, and the Schematron files were updated to ensure that all gml:ids under the report types (METAR, TAF, etc.) are UUIDs. Fixes #31 and fixes #33.

Note that another alternative would be to leave out the Schematron portions so that it is a recommended practice but not a mandatory practice

[blchoy]

This is to remind myself that I have to add the rule back into the EA post-transformation XSLT style sheets.

[braeckel]

As noted in my comment on the issue itself, the SCH updates also seem necessary and desirable despite the need for modifications by States when generating IWXXM messages