Dataflash viewer missing some events

I think MP's display of events is missing some recent additions that are available in Copter-3.6 including

DATA_GPS_PRIMARY_CHANGED = 67,
DATA_WINCH_RELAXED = 68,
DATA_WINCH_LENGTH_CONTROL = 69,
DATA_WINCH_RATE_CONTROL = 70,
DATA_ZIGZAG_STORE_A = 71,
DATA_ZIGZAG_STORE_B = 72,
DATA_LAND_REPO_ACTIVE = 73,

[the list can be found here in AP_Logger.h](https://github.com/ArduPilot/ardupilot/blob/master/libraries/AP_Logger/AP_Logger.h#L87) and is now shared across all vehicles.

Here is a screen shot showing the issue. As a side note I think we should actually remove the "DATA_" part at the front because I don't think this is very useful.

Start by locating Mission Planner's dataflash event display and compare its event list with the additions listed in AP_Logger.h. Confirm that DATA_GPS_PRIMARY_CHANGED through DATA_LAND_REPO_ACTIVE appear in the viewer, and decide whether the DATA_ prefix should remain based on the issue's requested display behavior.

Written by the indexing model from the issue text.