Remove old/inaccurate documentation file

I can’t find any evidence that this file is still meaningful.  The test it references are no longer pending or no longer present, and the URL it references doesn’t load meaningful information.

Also, to run the specs, #35 must be merged.

```bash
$ bundle && rake
Resolving dependencies...
Using rake 10.3.2
Using json 1.8.1
Using rdoc 3.12.2
Using xmpp4r 0.5.7 from source at .
Using bundler 1.7.6
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.
Run options:

# Running tests:

Finished tests in 2.725012s, 96.5133 tests/s, 514.8601 assertions/s.
263 tests, 1403 assertions, 0 failures, 0 errors, 0 skips

ruby -v: ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-darwin14.0]
```