ddox documentation generator

[Sönke Ludwig]

The documentation generator used for vibed.org (e.g.
http://vibed.org/api/vibe.core.file/FileStream) is now available as a
stand-alone project:

https://github.com/rejectedsoftware/ddox

also available as a VPM module:
http://registry.vibed.org/view_package/ddox

Features:

 - Supports DDOC sections and macros
 - Fully interlinked types
 - Automatically inherits members and documentation from base classes
 - Clean structure without endless spaghetti pages (customizable)
 - Diet template based and thus fully customizable output
 - Built-in HTTP server for local docs serving
 - Easily embeddable into existing vibe.d based sites
 - Can generate offline documentation as HTML files
 - Function for filtering the DMD .json file by module prefixes,
protection level and doc comment