Plane: fixed channel reversal in HIL

makes it possible to reverse channels
Git: ignore test.ArduPlane, test.APMrover2

Remove redundant dataflash.bin and eeprom.bin which are already covered
by *.bin exclusion
Copter: fixed vertical speed init for ALT_HOLD mode
AC_PosControl: fixed leash length calc for descent speed
AC_PosControl: update some comments re leash lengths
Copter: initialise vertical speed for Loiter mode
AP_Mission: initial draft library
AP_Mission: mostly working draft
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