AP_InertialNav: fix pos error degradation rate

degrate position_error to 10% over 2 seconds (assumes 5hz update rate)
must be *0.7943 instead of 0.7934
Copter: bug fix rally point landing target

was drifting toward home by some distance as (0,0,0) was hard-coded in
control_rtl.pde. Fixed, tested in SITL
Copter: ch7/8 switch for auto pause/continue

- added new mode for CH7/CH8 (#24, auto mission reset)
- changed mission.start() to mission.start_or_resume() in auto_init()
autotest: restore timeout in log download

this removes the debug code now that the issue has been found (it was
an old version of pymavlink causing the problem)
Mission: rename AUTORESET to RESTART
Copter: update release notes for AC3.2-rc1
Copter: remove unused servo_write function
Copter: remove unused Log_Write_GPS function
Copter: remove meaningless check from motor_test
Copter: version to AC3.2-rc1