Merged to current master commit:  41ba4a1ed217715d82a2c83e6a65686d3f035124, rmackay9 Copter: initialise ch7 and ch8 aux switches

AD_WPNav: added WPNAV_STPG_LSH user definable parameter for adjusting switching-stopping strength and smoothness

Copter: added FLTMODE_SSPD user definable parameter for adjusting mode switching speed 5 to 20 for fast to slightly slow speed

Copter: added FLTAUTO_MINTOA  parameter to set auto takeoff's target minimum altitude

Autotest. param_metadata:  added updated ParameterMetaData.xml file to display all newly added parameters' descriptions