compiler warnings
1. fix for optional XML elements
C89 compatibility etc.
handling of multiple exch. entries
Ticket #7
etbId comments fixed
Proposed change from errata
Ticket #111: 'unit', 'scale', 'offset' attributes missing in TRDP_DATASET_ELEMENT Ticket #102: XML parser needed Ticket #108: tau_marshall does not always work Ticket #88: Cleanup makefiles, remove dependencies on external libraries
Debugging aid
Ticket #110 (optional marshalling)
