revert: removed dedicated python nifxml library and moved xml files back

NifPlugins_VC80.sln

@@ -6,7 +6,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 	ProjectSection(SolutionItems) = preProject
 		MaxNifPlugins_Readme.txt = MaxNifPlugins_Readme.txt
 		MaxNifTools.ini = MaxNifTools.ini
-		..\docsys\nifxml\nif.xml = ..\docsys\nifxml\nif.xml
+		..\docsys\nif.xml = ..\docsys\nif.xml
 		NifPlugins_Development_Readme.txt = NifPlugins_Development_Readme.txt
 	EndProjectSection
 EndProject