Add --max-wait option to rec command for optimizing stdout inactivity
Make Ctrl-D key combo look like... key combo
Build also on Go 1.4
Remove debugging print
Workaround race condition when child process exits

There's race condition happening (so far observed only on CentOS) at the
moment when child process exits.  Sometimes reading from master fd
blocks forever even when the process is already reaped and there's no
more data to be read. Not sure what's the reason, it may be some CentOS
specific bug.

Using timeout does the job and seems to be relatively harmless.
Improve flag descriptions