Use constants for project and config file names

novelwriter/core/project.py

@@ -85,7 +85,6 @@ class NWProject:
         self.projDict    = None  # The spell check dictionary
         self.projSpell   = None  # The spell check language, if different than default
         self.projLang    = None  # The project language, used for builds
-        self.projFile    = None  # The file name of the project main XML file
         self.projFiles   = []    # A list of all files in the content folder on load
 
         # Project Meta
@@ -260,7 +259,6 @@ class NWProject:
         self.projDict    = None
         self.projSpell   = None
         self.projLang    = None
-        self.projFile    = nwFiles.PROJ_FILE
         self.projFiles   = []
         self.projName    = ""
         self.bookTitle   = ""
@@ -774,9 +772,9 @@ class NWProject:
         self._projTree.packXML(nwXML)
 
         # Write the xml tree to file
-        tempFile = os.path.join(self.projPath, self.projFile+"~")
-        saveFile = os.path.join(self.projPath, self.projFile)
-        backFile = os.path.join(self.projPath, self.projFile[:-3]+"bak")
+        tempFile = os.path.join(self.projPath, nwFiles.PROJ_FILE+"~")
+        saveFile = os.path.join(self.projPath, nwFiles.PROJ_FILE)
+        backFile = os.path.join(self.projPath, nwFiles.PROJ_FILE[:-3]+"bak")
         try:
             with open(tempFile, mode="wb") as outFile:
                 outFile.write(etree.tostring(