Hotfix release vibe.d 0.7.28

[Sönke Ludwig via Digitalmars-d-announce]

This is a small bugfix release that mainly fixes two critical regressions:

  - FreeListRef!T, which is used heavily in the HTTP server code, stored
    its reference count in an unallocated memory region, leading to
    possible memory leaks or memory corruption

  - A TCP connection with a non-empty write buffer that got closed by
    the remote peer and locally at the same time could result in the
    calling task to starve (i.e. it got never resumed after yielding
    execution). In particular, this could happen when accessing HTTPS
    servers with the HTTP client in conjunction with "Connection: close".

http://vibed.org/blog/posts/vibe-release-0.7.28