fix broken link
fixes namespace path to TestFixture
Merge pull request #2053 from Schlaefer/patch-1

fixes namespace path to TestFixture
Merge pull request #2052 from cakephp/3.0-broken-link

3.0 - broken link
Add upgrade tool to migration guide.

Refs #2054
[fr] update Time Helper

To follow en version
Merge pull request #2056 from cakephp/issue-2054

Add upgrade tool to migration guide.