Option to set the TextUnit id to be the same as the name in filters, especially the PropertiesFilter and XMLFilter

Created by: mike_bryant

It would be really nice for XLIFF workflows if there was an option to set the TextUnit id to match the name in filters (at the point they create a TextUnit). This is especially important for the PropertiesFilter and XMLFilter that have the ability to extract a unique ID from the content. Many XLIFF editors and workflows use the ID and not the resname for identification. For projects that place XLIFFs under source control it would also reduce the differences between versions of the file (integer IDs get reordered on updates).