Fix balutil handling of DisplayInternalUI

Virtually all changes to parsing BootstrapperApplicationData.xml need to be done in mbacore and balutil.

Also, fix Intellisense for dutil and typos/style in thmutil.
No, but balutil, deputil, and wcautil all already had this.  I thought importing .props at the beginning and .targets at the end was the standard thing to do anyway?