[fix] Handle socket errors
[dist] Bump version to 0.8.6
[fix] Handle errors on request object

Sometimes a request emits `error` event with a `Parse Error`.
[fix] Don't remove `error` listener after response ends

In some rare cases, `error` event might still be emitted after the
response has ended. This is (most likely) a bug in the `node` core.
[dist] Bump version to 0.8.7
Merge remote-tracking branch 'upstream/master'

Conflicts:
	lib/node-http-proxy/http-proxy.js