= caching: Upgrade to concurrentlinkedhashmap 1.4

Fixes #450

The upgrade was relatively simple. I had to adjust a few values in the test because CLHM 1.4 uses a slightly different backing map which changes the order of values in the toString output but (it seems) in a predictable way.
Merge pull request #481 from agemooij/issue-450

= caching: Upgrade to concurrentlinkedhashmap 1.4