1. Nodes cache previous relative paths so that they do not have to
parse the paths each time.
2. There are new getNode() methods that include indices, so that users
do not have to sprintf to a buffer to iterate through indexed nodes.
TRACE_READ - log a message whenever the property is read.
TRACE_WRITE - log a message whenever the property is written.
The second one works only when the property value is changed through
the property manager; tied variables and accessors are not polled for
value changes because of the performance hit.
These methods end up invoking private methods
SGPropertyNode::trace_read and SGPropertyNode::trace_write. By
setting breakpoints on these methods inside a debugger, it is possible
to debug property access and find what parts of a program are reading
or writing specific property values by doing a backtrace.
In the XML property files, users can use the attributes 'trace-read'
and 'trace-write' to control tracing; the value should be 'y' to
enable tracing or 'n' to disable it (the default).
david