Allow users to designate folders with properties in QL

I am assigning this to HV initially. Please re-assign or not as you see fit.

Currently, if a QL data provider wants to group data sets into folders, she has to use the "slash-hack."

That is, she has to use strings like the following to get IGB to organize data sets into folders.

For example, to get the data set "foo" to appear in folder "bar," the annots.xml has to look like this:

<file name="bar/foo"/>

This is awkward and also makes it impossible to associate "i" buttons and other other attributes to the folder.

I would like to propose that we modify the annots.xml format to allow "folder" tags, that would look like this:

<folder name="bar" url="http://www.example.com" description="Data files you might like">
<file name="foo" url="http://www.example.com/foo" description="A really great data set"/>
</folder>

Moreover, folder tags would be able to contain other folders as well as files.

Last but not least, the order the folders and files appear in the annots.xml file should dictate the order they appear in the IGB Data Access Panel's Data Source and Data Sets window.