Add support for adding docstrings and urls to def files.
Add doc urls to ecma5.json
Make sure types with urls/docs defined on them are not shared
Add links to defs/browser.json

(As gathered automatically from MDN. Some might not be great.)
Update outdated sentence in index.html
GET calls validate path instead of pathname

path includes query parameters whereas pathname does not. The code as originally written will always fail when supplying query parameters as "/" != "/?doc={}".
Change pluginOptions to plugins
Only pass one plugin option in test.js
Add custom @columnNumber suffix for completion hint tests to allow intra-line testing
Simplify handling of @ in completion tests
Add docstrings to the ecma5 definitions
Show docstrings below editor when picking completions in demo
Add docstrings to browser.json
Improve display of docstrings in demo somewhat
Add urls and docstrings to node.js definitions
Show docstring and link when doing ctrl-i in the demo
Added descriptions and doc links for jQuery functions and properties.  Links go directly to the appropriate page at http://api.jquery.com/, and the description comes from the short tag descriptions on that site
[jquery defs] Remove Deferred.when -- it doesn't appear to exist

Issue #38
Use workList instead of recursion for propagation, more reliable approach to cut-off
Clear AVal's .proto caches when purging types from them

Closes #36