The bug fix for the race condition on handler execution used the new
strand interface. While it is possible to use bind_executor on every
call, that is error prone and not the suggested usage anymore.

No idea, if that is secure yet.

Since it is depreated it will also be removed in the future.
Fixes #7

Add .well-known support

Basic support for room upgrade handling.  Closes PR #18

Build lib as Shared Object

Build mtxclient as a shared object. No longer statically link boost libs during build.

Fix mismatch between new[] and delete with Olm objects.  Thanks @MonokelPinguin 

Fix CI issues w/ mtxclient.  Thanks to @MonokelPinguin 

Current AppVeyor image includes a very old vcpkg snapshot. Because of
that, this doesn't include https://github.com/Microsoft/vcpkg/pull/5258
specifically
https://github.com/Microsoft/vcpkg/pull/5258/commits/c895bb658d52bee471169460c711fdd90e3d5b7b

Because of that, find_package only works for find_package(nlohmann-json)
but not find_package(nlohmann_json). Updating the ports cache should fix
that.