Policy Plus - List element handling

I had planned to finally implement the "save policy changes to disk and Registry" feature today, but the Windows 10 version 1607 upgrade took really long, so I didn't get to do all I wanted. I did manage to add an editor for <list> policy elements, which was missing before. Clicking the Edit button on one of those elements produces an editor dialog very reminiscent of the one in the real Group Policy Editor.

For elements that allow the user to provide names, the dialog grows a Name column.

I also found a bug in PolFile's importing of string values. Previously, it could read strings fine, but writing them back would butcher their encoding.

In terms of progress toward saving to disk, I dug in a little deeper on how Group Policy knows a refresh is needed. There's (sometimes) a "Group Policy Objects" subkey in the Registry that contains all the entries from the corresponding POL file, and a "Group Policy" subkey that keeps track of information on the active GPOs. That last thing includes a "version" value, but it doesn't quite match with the version in gpt.ini, so I'm not sure what its significance is.