Stopped postFixOps warning in play.api.test.Helpers
Reverted buggy #1522 asset controller changes and wrote new tests

These tests will be useful when refactoring the controller. They will be
used to ensure that behaviour doesn't change unintentionally.
Introduced methods for decoding URI paths and path segments
Assets controller support for encoded paths, works on Windows

- Fixes #1593, which is a regression introduced by #1522 and c0a84ac.
- No longer uses File.toURI on the base directory, as this didn't
  work properly on Windows. Instead URL path decoding is done manually
  using `UriEncoding.decodePath`.
- Removed the test file "foo+bar: baz.txt" because it caused errors
  when unzipping the Play distribution on Windows. Our tests still
  adequately cover this case.
Merge pull request #1593 from richdougherty/win-assets

Assets not being served on Windows