XLALSnglBurstAssignIDs() XLALSimBurstAssignIDs()

- move from lalburst to lalmetaio
- completes the gathering of XML I/O related functions in lalmetaio.  other "assign IDs" functions are already in lalmetaio
- there are still functions for manipulating linked lists of row objects in other libraries, but these functions tend to be used as the last thing done in a program before writing the document to disk, i.e., they are more a part of the document writing code, than document contents manipulation code.
42 jobs for lalmetaio_cleanup_04 in 115 minutes and 57 seconds (queued for 37 minutes and 8 seconds)