Ready for testing: vibe.d 0.7.26-alpha.3

[Sönke Ludwig via Digitalmars-d]

Despite it's name, this release should be considered a beta release. PR 
#1268[1] will potentially still make it in, but otherwise only bug 
fixing will happen at this point. As with the previous versions, the 
final release will happen at the same time as DMD 2.069.0. Please use 
the chance to test for any remaining issues (simply run `dub upgrade 
--prerelease` on your project(s)).

Changes in this release:
https://github.com/rejectedsoftware/vibe.d/blob/master/CHANGELOG.md
[1]: https://github.com/rejectedsoftware/vibe.d/pull/1268