CSV export: allow spaces on filename and fix tests

app/src/androidTest/java/org/isoron/uhabits/unit/models/HabitTest.java

@@ -366,9 +366,9 @@ public class HabitTest extends BaseTest
         HabitFixtures.createShortHabit();
 
         String expectedCSV =
-                "Name,Description,NumRepetitions,Interval,Color\n" +
-                "Meditate,Did you meditate this morning?,1,1,#AFB42B\n" +
-                "Wake up early,Did you wake up before 6am?,2,3,#00897B\n";
+                "Position,Name,Description,NumRepetitions,Interval,Color\n" +
+                "001,Meditate,Did you meditate this morning?,1,1,#AFB42B\n" +
+                "002,Wake up early,Did you wake up before 6am?,2,3,#00897B\n";
 
         StringWriter writer = new StringWriter();
         Habit.writeCSV(Habit.getAll(true), writer);

app/src/main/java/org/isoron/uhabits/io/HabitsCSVExporter.java

@@ -81,7 +81,7 @@ public class HabitsCSVExporter
     @NonNull
     private String sanitizeFilename(String name)
     {
-        String s = name.replaceAll("[^a-zA-Z0-9\\._-]+", "");
+        String s = name.replaceAll("[^ a-zA-Z0-9\\._-]+", "");
         return s.substring(0, Math.min(s.length(), 100));
     }