AP_Mission: fixes to protect against endless loops
AP_Mission: tests added to example sketch
AP_Mission: replace block read/write for eeprom

Also reserve command #0 for home position
Copter: add AP_Mission object parameter

Remove global command_total and command_index parameters
Copter: instantiate AP_Mission object
Copter: remove low-level handling of mission cmds

Now handled by AP_Mission
Copter: add mavlink packet to cmd conversion to GCS_Mavlink.pde
Copter: ch7 save wp feature to use ap_mission
Copter: log using mission commands
Copter: process cmds from mission lib
Copter: remove unused definitions
AP_Mission: special handling for cmd
Copter: pass ahrs into mission constructor
Mission: add mavlink to cmd conversion methods
Mission: fix example sketch
Common: add location options masks
Plane: use common location options masks
Rover: use common location options masks
Copter: use Mission mav to cmd conversion methods
Copter: use common location options masks