Add a simple sandbox for running experiments.

We do not expose any functions to the sandbox, so it's pretty useless right now.
Add a simple DNS lookup primitive
Refactor experiments to use a sandboxed API.
Move serialization inside the sandbox.
Upload results upon exit.
Let DNS resolver specify a resolver
Put serialization in the sandbox.
Add dns test for looking up Alex domains.

This is just an example. It doesn't record a lot of important information you
want from a DNS test, like timestamps, number of results, etc.
alex -> alexa
Add missing file.
Add comment about Alexa 100.
Reimplement most of the main code in C.
Move DNS test into the main binary
Comments
Add missing dns.h header
gitignore
Move sandboxing entirely to C.
Remove obsolete files.
Function comment
Restructure source.