Show ELAN free translations at bottom and with quotes

[sciepsilon]

In preprocessing, mark a tier as "free-trans" if it's the direct, non-subdivided child of an independent tier. (Eventually, we also want to mark grandchildren etc. of independent tiers, but only if none of their ancestors are subdivided.)

Then, in frontend, display "free-trans" tiers in the bottom row, with quotes around them.

[nickatomlin]

I believe this issue also affects FLEx files. The "Singo a'i" demo was working for a while, but only because I manually moved the free translation tier to the bottom of the XML file.

[nickatomlin]

The current fix (#85) is not correct in many ways.


In particular, the re-ordering does not re-order tier checkboxes, which can be quite confusing.

[sciepsilon]

The relevant attribute is named "subdivided"