tree checksum vpatch file

all signers: asciilifeform bvt diana_coman

antecedents: ffa_ch5_egypt.kv

press order:

ffa_ch1_genesis.kvasciilifeform bvt diana_coman
ffa_ch2_logicals.kvasciilifeform bvt diana_coman
ffa_ch3_shifts.kvasciilifeform bvt diana_coman
ffa_ch4_ffacalc.kvasciilifeform bvt diana_coman
ffa_ch5_egypt.kvasciilifeform bvt diana_coman
ffa_ch6_simplest_rsa.kvasciilifeform bvt diana_coman

hunks:
ffa/ffacalc/ffa_calc.adb
ffa/libffa/fz_modex.adb
ffa/libffa/fz_modex.ads