handle ECONNRESET upon early stdin end

related to https://github.com/stream-utils/duplex-child-process/pull/4
Fix corner case of a test

this.read() is null in subsequent readable events
Merge pull request #6 from jeromew/patch-1

Fix corner case of a test
Merge pull request #5 from jeromew/patch-3

handle ECONNRESET upon early stdin end
0.0.3
Add `combined` stream tests to show that there is a problem with stream-stream