Fix for message body summary multibyte split

Fix for message body summary multibyte split

Fix utf8 mb char splitting in body summary

Prepare for 1.7.0 release (#353)

* Prepare for 1.7.0 release

* minor

Merge pull request #283 from guzzle/null-header-value

Accept null and bool header values again

fix changelog title levels

Release 1.5.2

Release 1.5.1

Release 1.5.0

* Reverted BC break to `Uri::resolve` and `Uri::removeDotSegments` by…

… removing

  calls to `trigger_error` when deprecated methods are invoked.