updates to book_changes RPC command #3688

Job	Run time
dependencies (linux, gcc, Debug)	3m 25s
dependencies (linux, gcc, Release)	2m 10s
dependencies (linux, clang, Debug)	2m 55s
dependencies (linux, clang, Release)	2m 18s
conan	2m 47s
coverage (linux, gcc, Debug)	13m 1s
test (linux, gcc, Debug)	10m 56s
test (linux, gcc, Debug, -Dunity=ON)	7m 45s
test (linux, gcc, Release)	11m 44s
test (linux, gcc, Release, -Dunity=ON)	8m 12s
test (linux, clang, Debug)	9m 20s
test (linux, clang, Debug, -Dunity=ON)	6m 11s
test (linux, clang, Release)	10m 54s
test (linux, clang, Release, -Dunity=ON)	8m 19s
	1h 39m 57s

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