Fix wording in exception handling

An exception should be thrown when exceptions option is set to true, not false.
Merge pull request #635 from gjuric/patch-1

Fix wording in exception handling
4.0.2 release
Updated test Server class to make sure server is started on flush()
Merge pull request #640 from guzzle/fix-server

Updated test Server class to make sure server is started on flush()
Added an emitter option to the Client
Merge pull request #642 from guzzle/fix-inject-emitter

Added an emitter option to the Client
Fixing some CI bugs
Fix examples syntax typo.
Merge pull request #645 from KayLeung/patch-1

Fix examples syntax typo.
Merge branch 'master' of https://github.com/guzzle/guzzle

Conflicts:
	src/Client.php