Improve Unicode support #1520

Job	Run time
cppcheck	1m 50s
min features with gcc	3m 10s
code formatting check	30s
min features with g++	2m 49s
min features with clang	2m 34s
max features with gcc	3m 34s
max features with g++	2m 39s
max features with clang	4m 54s
max features with gcc and DEBUG	2m 35s
max features with gcc for 32-bit arch (legacy OS)	1m 58s
max features with g++ for 32-bit arch (legacy OS)	1m 48s
max features with clang for 32-bit arch (legacy OS)	1m 55s
	30m 16s

Provide feedback