Make BinaryPeek Disposable and catch WebExceptions.
* ChanTools.cs: Make sure we don't say we support archive.moe image
  links.

* MinimalWeb.cs: Prevent 403 Forbidden and fix NPE in Dispose.
Improve bin trigger parsing, try to query each argument.
Change ImageProperties to MediaProperties, make it a class and add a
Duration member. ImageType => MediaType and ImageInfo => MediaInfo.
Ebml parser, so we can parse Matroska and WebM.
Make ReadInto more useable by returning true if it read everything
into the array and false if it for whatever reason didn't
(end-of-stream).