Merge branch '1.6' of git+ssh://github.com/tarantool/tarantool into 1.6

src/box/CMakeLists.txt

src/box/box.cc

src/box/func.cc

src/box/lua/call.cc

src/box/lua/call.h

src/box/lua/schema.lua

src/box/port.cc

src/box/port.h

src/ffisyms.cc

test/app/function1.c

test/app/function1.result

test/app/function1.test.lua