psr-0 should have been psr-4 when switching to it

Update child repos to PSR-4 for git subs-plit

Use parse_url() to check for port

Merge remote-tracking branch 'origin/master' into 0.3

* origin/master:
  Change react/promise constraints to use tilde operator

Conflicts:
	composer.lock
	src/React/Dns/composer.json
	src/React/Stream/composer.json

Merge branch 'unused-code' of github.com:reactphp/react

Fix examples in react/dns README

Split first method call in chain to new line

Rename $resolver to $dns in examples

This is partially to prevent clashes in the future with React/Promise,
which includes a separate concept of resolvers.

It also is more intuitive to newcomers, and reads nicer in general.

[Dns] added RetryExecutor

Replace calls to array_merge with array_values