Shuffle around 5dtUSB includes and get rid of an iostream include
Add initial version of message macros header.
Replace all the message macros I could find.

Grepped for _INFO to manually remove definitions and add a header include.

Changed calls by using this script:

#!/bin/sh
for prefix in MC _5DT SPI DO IDEA NIK VRPN DT FT ZAB; do
    sed -i -e "s/${prefix}_INFO/VRPN_MSG_INFO/g" -e "s/${prefix}_WARNING/VRPN_MSG_WARNING/g" -e "s/${prefix}_ERROR/VRPN_MSG_ERROR/g" *.C
done
Compile fix - apparently not all the macros were identical due to multiple base classes.
Add vrpn_TimevalDurationSeconds to vrpn_Shared.
Replace a macro with an inline function.
Remove all duration functions, replacing with vrpn_TimevalDuration or vrpn_TimevalDurationSeconds.
Pulled down update to latest json submodule version.
Merge branch 'duration' of https://github.com/rpavlik/vrpn
Reverting switch to stream-oriented send_text_message that had been inserted by recent merge.  Still debugging an issue where this type of output hung on one architecture.
Fixing merge collisions.