Path: Change filenames in the rest of the Path code

Reflects changes in 
* PathOpGui.SetupOperation()
* GetResources()
* sPIxmap
* pixmap
* *.UI files

Also contains minor translation context renames (these were edits made near to original intent of this commit)

src/Mod/Path/PathScripts/post/gcode_pre.py

@@ -112,7 +112,11 @@ def insert(filename, docname):
 
         # Create a custom and viewobject
         obj = PathCustom.Create("Custom")
-        res = PathOpGui.CommandResources('Custom', PathCustom.Create, PathCustomGui.TaskPanelOpPage, 'Path-Custom', 'Path-Custom', '', '')
+        res = PathOpGui.CommandResources('Custom',
+            PathCustom.Create, PathCustomGui.TaskPanelOpPage,
+            'Path_Custom', 
+            'Path_Custom', '', ''
+            )
         obj.ViewObject.Proxy = PathOpGui.ViewProvider(obj.ViewObject, res)
         obj.ViewObject.Proxy.setDeleteObjectsOnReject(False)