Add orbname to metadata
Add orbname to datalogger metadata
add orbpktid; rx_timestamp now int

rx_timestamp was a string for archaic reasons, should be an int

The pktid from the orbserver was not being passed along with the
metadata, now it is.
Fix default exception handler in on_get

The default exception handler was failing due to an undefined variable.
Now prints a full traceback instead of just the exception message
Add sources to metadata

The instance metadata now contains information about all of the orb
sources that provide data for the instance. The oldest source name is
provided, as is a timestamp for that oldest source name.
Merge branch 'srcname_metadata'