Added missing definitions, Sys.Debug tests

Added missing properties to Component definitions.
Added debug tests.
Fixed invalid definitions for Debug class, documentation doesn't state
that these methods are static, but the examples appear that Debug is
singleton and methods are static.

Cleaned up Observer definition methods / properties.

Sys.Res Tests have been added and definitions added missing static.
Added Sys.StringBuilder tests
Cleaned up StringBuilder ToString definition overload with optional parameter.
Sys.EventArgs definitions and tests
Region cleanup for Web Essentials //#region support.
Added NetworkRequestEventArgs and WebRequestManager definitions and tests.
Added PageRequestManager Tests and EndRequestEventArgs Tests
Minor changes to PageRequestManager definitions and Browser
Added error fields to test.
Merge pull request #2253 from pjmagee/master

Added further definitions and Tests. Fixed some invalid definitions.