Move test program to submodule

[slhmy]

Solve #85.

Additionally fixed SETUP_ENV bash.
Dev env should be usable for cargo test if you run git submodule update --init --recursive.

[akamya997]

It seems good, but I think some guides should be added to README.md so that it could help others build the developing environment from scratch.
BTW, though it is enough now, but I hope that we can remove the binary files as well as the testlib.h in the future.

[slhmy]

I'm merging this PR right now, for the known issues can be fixed later.