Correct writeXmlDoc.addMembers

[ReedCopsey]

Prevent members from being added to the global member list when the
xmlDoc contains no content.

Fixes#148

[latkin]

Can you add a quick test under tests\fsharpqa\Source\XmlDoc\Basic? Just to make sure garbage elements are no longer generated.

[ReedCopsey]

@latkin Done. New xmlDoc005.fs test checks to make sure that names are generated for "Class1" but that there are no empty member names. This fails in current build, passes after this fix.

[latkin]

Some of the existing XMLDoc tests (under XmlDoc\UnitOfMeasure) are now failing due to the change. Can you take a look and see if the tests need updating to match new (correct) behavior, or if there is some regression?

[enricosada]

👍 great

[ReedCopsey]

@latkin Corrected those tests. Sorry I missed that the first round. This update should correct those tests to match the new, better generated content.

In general, these tests are fairly brittle. They're all based on specific ordering of the XML (which, actually, is kind of backwards now, though fixing would break most of the tests again.) It might make sense, in the longer run, to revisit how they're setup and run.