Plane: version to 4.5.7 #923

Job	Run time
build-gcc-heli	8m 56s
build (base)	8m 47s
build (clang)	11m 1s
autotest (sitltest-copter-tests1a)	11m 56s
autotest (sitltest-copter-tests1b)	13m 35s
autotest (sitltest-copter-tests1c)	12m 11s
autotest (sitltest-copter-tests1d)	12m 2s
autotest (sitltest-copter-tests1e)	13m 27s
autotest (sitltest-copter-tests2a)	13m 17s
autotest (sitltest-copter-tests2b)	22m 52s
autotest-heli (sitltest-heli)	11m 53s
	2h 19m 57s

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