[DTI] - Verify and complete DTI interface

[jr1221]

Observed Behavior

Since we have a DTI MC and we have Calypso to compare to, lets verify dti.c is operational for all messages. It would often give endian_swap issues.

Steps to Reproduce

1. Call the code to the dti to do something
2. Compare what number you called to that which is displayed in MQTTUI. Fix as appropriate.

[jr1221]

Also use endian swap where it makes sense instead of bit shifting.

[jr1221]

Also remove remnants of get_mph using a global variable.