This should "just work", and can build on the resolution to #68 .
https://www.google.com/search?q=http_proxy

This would allow proxying behind a corporate firewall without any/every 3rd party module using axios requiring code changes to support proxying.

test/specs/core/mergeConfig.spec.js
c[key] = { user: 'foo', pass: 'test' }
      expect(mergeConfig(a, b)).toEqual(c);
    });
    it('should merge ' + key + ' with defaults', function() {
      var a = {}, b = {}, c = {};
      a[key] = { user: 'foo', pass: 'bar' };
      b[key] = { pass: 'test' };
      c[key] = { user: 'foo', pass: 'test' };
      expect(mergeConfig(a, b)).toEqual(c);
    });
    it('should overwrite default ' + key + ' with a non-object value', function() {
      [false, null, 123].forEach(function(value) {
        var a = {}, b = {}, c = {};
        a[key] = { user: 'foo', pass: 'test' };
        b[key] = value;
        c[key] = value;
        expect(mergeConfig(a, b)).toEqual(c);
      });
    });
  });
  it('should allow setting other options', function() {
    var merged = mergeConfig(defaults, { timeout: 123 });
    expect(merged.timeout).toEqual(123);
  });
  it('should allow setting custom options', function() {
    var merged = mergeConfig(defaults, { foo: 'bar' });
    expect(merged.foo).toEqual('bar');
  });
});