Always throw JSONException from vibe.data.json

Publicly import JSONException from std.json and modify
the documentation accordingly.
Throw WebSocketException from vibe.http.websockets

Add WebSocketException class and modify documentation accordingly.
Make vibe.d work without OpenSSL (VibeNoSSL) and add factory functions.

Instead of using SSLStream's and SSLContext's constructors directly, using free functions will be required at some point, so that those classes can be changed to interfaces with multiple underlying implementations.
Ignore logging exceptions in release mode and display the exception message in debug mode.
Merge pull request #590 from lultimouomo/typedExceptions

Use typed exceptions in vibe.data.json and vibe.http.websocket
Fix typo.
Update change log.
Merge branch 'master' of https://github.com/rejectedsoftware/vibe.d