Excude all unneeded prefixes (we don't want the xd prefix in the output for example).
Rename file based on XML encoding standard name.
A gmd:date with a nilReason attribute is emptied.

When a gmd:date has a nilReason attribute (with whatever value eg. withheld), the element is emptied.
The nilReason attribute should be copied but the children should not be affected by this attribute.
Also a gco:DateTime is xs:dateTime and can't have attribute. No need to copy the nilReason attribute to this element.
Externalize the add namespace section to a specific template because it can be used in a number of XSLT.
Add first draft conversion from iso19115-3 to iso19139. This transformation is useful for catalog managing metadata records in iso19115-3 format and providing a CSW endpoint following also the iso19139 schema.
Merge pull request #26 from fxprunayre/improvements/iso19139-to-115-3-and-reverse-and-fix-date-with-nilReason

Add ISO19115-3 to ISO19139 conversion and fix date with nil reason