libneubot.json: make the comment multiline
libneubot.json: update the comment
Add async DNS resolver functionality

This functionality is implemented using libevent evdns.

Bump the minor version number, because this adds new
functions to the libneubot API.
Automatically generate libneubot.py wrappers

These wrappers make sure that the C functions return value
makes sense, otherwise, they raise exceptions.

To implement this feature, I needed to add a new pseudo-type
in libneubot.js, i.e., status_t, which is an integer type
that is 0 on success and nonzero on failure.