Update common.xml

Proposal to add direct battery charge and energy consumption reporting in addition or instead of the current percentage of battery.  

The problem with the battery percentage is that the on-board system in most cases does not natively know the size of the energy storage and relies on the (possibly) configured battery capacity value.  In case of changing the battery on the field there may be different battery size or there may be a different type of power source on board. In any case, the percentage value is secondary information and dependent on a pre-configured capacity value, which may or may not be correct or relevant.  

If the on-board system has capability to report any consumption numbers, it almost certainly is measuring current and voltage samples.  These are primary information available to be reported and should be reported.

Possibly it could make sense to split message 147 to two separate messages: 1) multi-cell battery individual cell voltage reporting 2) total voltage & current readings and derivatives.
1. Fixed field closing tag.  2. Increased current and energy consumption field sizes.

Field size increase to accommodate kilowatt-size power trains and long missions. A more airlink economical option would be to use one scalar byte for both of the consumption fields.  However, not sure if the savings would carry their weight in added complexity.
mavwp: added support functions for fence editing
pymavlink: added add_latlonalt() for waypoint map editing
APM: changed SIMSTATE to use int32_t lat/lon

this allows us to test the full accuracy of GPS drivers. Note that
SIMSTATE is only used by mavproxy at the moment, so changing this
doesn't break anything else
mavutil: changed mavlink_connection() to support open retries on TCP

this avoids race conditions in SITL startup
mavextra: added airspeed_ratio() and improved gps velocity
pymavlink: fixed generator to run from installed package
messages: added MAV_CMD_DO_SET_ROI

this is used by ArduCopter
pymavlink: update version
ardupilotmega: added AIRSPEED_AUTOCAL message

used for debugging airspeed calibration EKF
pymavlink: fixed mag_heading() calculation
pymavlink: added used_ratio to airspeed() function
pymavlink: added wrap_360() function
added tools to determine compass rotation given GPS or GYRO data
nicer output from magfit_rotation_gyro.py
magfit_rotation_gyro: cope with AHRS_ORIENTATION and COMPASS_ORIENT
magfit_rotations_gyro: fixed bug
Add MAV_CMD_NAV_START_RX_PAIR to COMMAND_LONG enum

- Provide for a better way to start receiver pairing
Move MAV_CMD_START_RX_PAIR to common COMMAND_LONG messages