Released vibe.d 0.9.8

[Sönke Ludwig]

Just a quick announcement for a new vibe.d release that, probably most 
notably, gets rid of most DIP1000 related deprecation warnings. It also 
brings two breaking changes in the form of deprecating 
vibe.utils.hashmap in favor of the new vibe-container package, as well 
as requiring REST interfaces to be fully @safe.

There is also a bunch of smaller additions and fixes, as listed in the 
change log: https://vibed.org/blog/posts/vibe-release-0.9.8

Although it follows a different version track, vibe-core has also 
received some notable changes during this time frame, such as heavily 
improved performance of ManualEvent, which is the basis for all 
synchronization primitives, a new performInWorker function, 
TaskSemaphore, Monitor!T, yieldUninterruptible and a dedicated thread 
pool for I/O operations.

The next release of vibe.d (0.10.0) is expected to land sooner than 
usual and will contain a substantial restructuring of the package 
structure. All low level modules that are currently sub packages of 
"vibe-d" will be broken out to separate standalone packages, as well as 
the "vibe-d:http" package. This will pave the way for *finally* being 
able to work towards integrating the work on a HTTP/2 implementation 
that was carried out by Francesco Galla during SAoC 2018.