[#3714] Fix issues with 5.3.3 polyfills

- When installing the entire framework, the `autoload.files` of
  `composer.json` are sorted alphabetically. This causes an issue, as
  the `Zend\Session` polyfill depends on the `Zend\Stdlib` polyfill.
- When installing the components separately, they are sorted based on
  dependencies, and thus the require statements happen in the correct
  order.
- The solution presented here is to test if (a) the polyfill class is
  already declared, and (b) if not, attempt to load the polyfill based
  on the known directory structure.
Fix #3852

Added test case from the aforementioned issue.
No longer reversing regex as it was problematic for constraints.
Fixing expectation for two optional subdomains with one missing.
Adding test cases for nested subdomains.
Removing comments RE: reverse regex
Merge branch 'hotfix/3855'

Close #3855
Fixes #3852
Merge commit 'refs/pull/3714/head' of github.com:zendframework/zf2

PR #3714
Fix-simple-route
Fix bug with mixed case
Merge branch 'simple-route-case-insensitive' of git://github.com/bakura10/zf2 into hotfix/3856
Merge branch 'hotfix/3856'

Close #3856
[2.1.3] release prep

- Updated changelog
- Updated readme
- Updated Zend\Version
Merge branch 'releases/2.1.3'

2.1.3 readiness
Version bumped to 2.1.4dev
Merge branch 'version/bump'

Bump to 2.1.4dev