Don't spin in epoll_wait() / kevent() / port_getn() / etc. when we can't
accept() a new connection due to having reached the file descriptor limit.
Pass the error to the connection_cb and let the libuv user deal with it.

Remove the O_NONBLOCK flag from file descriptors 0-2, most applications don't
expect EAGAIN errors when dealing with stdio.

Make uv_cpu_info() understand the ARM and MIPS versions of /proc/cpuinfo,
it only knew how to deal with the x86 version

This commit also fixes a buglet where uv_cpu_info() reported the maximum CPU
frequency instead of the actual CPU frequency. That is, before this commit
`out/Debug/run-tests platform_output | grep speed | sort | uniq -c` on my
system always reported:

      8   speed: 3400

Now it reports (for example):

      2   speed: 3400
      6   speed: 1600

In other words, two CPUs are running at full speed while the others have been
scaled back because they're mostly idle.

This is a back-port of commit 54bfb66 from the master branch.

Fixes #526.

This is a backport of 2 patches by Ting-Yu Lin and Hiroaki Nakamura.

Makes the new process name visible in both `ps` and `ps a`, with the caveat
that `ps` will only print the first 16 characters.

Before this commit, `ps` kept reporting the old process name.

Guard against the possibility that the queue is emptied while we're iterating
over it. Simple test case:

  #include "ngx-queue.h"
  #include <assert.h>

  int main(void) {
    ngx_queue_t h;
    ngx_queue_t v[2];
    ngx_queue_t* q;
    unsigned n = 0;
    ngx_queue_init(&h);
    ngx_queue_insert_tail(&h, v + 0);
    ngx_queue_insert_tail(&h, v + 1);
    ngx_queue_foreach(q, &h) {
      ngx_queue_remove(v + 0);
      ngx_queue_remove(v + 1);
      n++;
    }
    assert(n == 1); // *not* 2
    return 0;
  }

Fixes #605.