When loading data from a snapshot, validate tuples

.gitignore

cmake/BuildMisc.cmake

include/pickle.h

src/box/box.m

src/box/tuple.h

src/box/tuple.m

test/unit/CMakeLists.txt

test/unit/base64.c

test/unit/base64.result

test/unit/base64.test

test/unit/unit.h

third_party/base64.c

third_party/base64.h