Simplify PdmDocument class and move fileName to private

Remove resolveReferencesRecursively() and initAfterReadRecursively() from PdmDocument::readFile(). These functions will be called in RiaApplication::loadProject after the file paths modifications are done. This will ensure that file paths can be used in initAfterRead() functions.

ApplicationLibCode/UnitTests/RimRelocatePath-Test.cpp

@@ -59,7 +59,7 @@ TEST( RimRelocatePathTest, findPathsInProjectFile )
 
     RimProject project;
 
-    project.fileName = fileName;
+    project.setFileName( fileName );
     project.readFile();
 
     std::vector<caf::FilePath*> filePaths;