vchoi_fork

Refactor argument tracing to implement new capability for tracing arguments
of non-API routines, with the H5ARG_TRACE macro.   This macro is updated
automatically with the bin/trace script that runs as part of the autogen.sh
process.   Major changes were in src/H5trace.c and bin/trace, with the other
changes being cleanups to the argument lists, to improve their presentation
in the tracing output.

Also - added the "managed string" routines, which can dynamically allocate
strings, appending printf-formatted output to the string efficiently.