Add registerPlugin function.

More details: http://developer.longtailvideo.com/trac/browser/sdks/jw6-plugin-sdk/docs/plugins-js.html
Beginning of microsoft ajax definitions

This is preliminary and is the foundation. Still need to add to the
namespaces that have been declared and port over documentation including
testing and re-view all static methods and event handler function
arguments.

No testing has been completed.
Added WebForms namespace.

Added some preliminary classes from documentation.
Formatting changes.
Added UI classes to the definitions

Still need to add methods, properties, fields, events
Add missing _.mapValues type definition
Add method documentation
Use tabs instead of spaces, like the rest of the file
Added Type definitions
Use generic parameter
Fixed some JSDocs and finished Component

Added CultureInfo definition
Sys classes added definitions need to be added.

Added and defined IContainer interface, other interfaces need to be
defined.
Added more defnitions and added @see JSDoc

Including CollectionChange, Observer, Enumeration, IDisposable,
INotifyDisposing, INotifyPropertyChanged including
NotifyCollectionChangedEventArgs
Enabling 'when.d.ts' to be also usable as an external module so that is can be included like 'import When = require(../when/when);'
Added more definitions from the documentation

Mainly in the Sys Namespace.
Added BeginRequestEventArgs defintion
Added more definitions
Added signature_pad.d.ts definitions
Test file for signature_pad
Updated signature_pad.d.ts file