AP_RangeFinder: allow for more than 327m range

[peterbarker]

[peterbarker]

Board                    AP_Periph  blimp  bootloader  copter  heli  iofirmware  plane  rover  sub
CubeOrange-periph-heavy  8                                                                     
Durandal                            48     *           200     248               208    264    264
Hitec-Airspeed           *                                                                     
KakuteH7-bdshot                     96     *           328     336               176    264    288
MatekF405                           -8     *           224     200               288    184    200
Pixhawk1-1M-bdshot                  8                  144     312               352    232    224
f103-QiotekPeriph        *                                                                     
f303-Universal           336                                                                   
iomcu                                                                *                         
revo-mini                           32     *           288     280               608    232    304
skyviper-v2450                                         48                                      

[peterbarker]

Parameter upgrade was tested with this:

./Tools/autotest/test_param_upgrade.py --vehicle=arducopter --param "RNGFND1_MAX_CM=300->RNGFND1_MAX=3.00" --param "RNGFND2_MIN_CM=678->RNGFND2_MIN=6.78" --param "RNGFNDA_MIN_CM=1->RNGFNDA_MIN=0.01" --param "RNGFND5_GNDCLEAR=103->RNGFND5_GNDCLR=1.03"