Custom barline at start of system lost on save/reload

Ubuntu 14.04, GIT commit: 5b20a4a

1) My First Score
2) Style / General / Barlines, Barline at start of single staff
3) Click barline at start of second system
4) Double click "Double barline" in Barlines palette to apply it
5) Save
6) Close
7) Load

Result: the double bar is lost. This is true in 2.0.2 and in master. As far as I can tell, it is written to the file as an integer (the raw enum value) but the read code is expecting a name. Probably we shoudl be writing names, but maybe in fixing this we could accept either, to automatically fix older scores. Right now we are writing the tag using writeProperty(), and I guess we'd have to change this to write the tag directly and do the conversion.