Our files are up to a decade old, and have churned so much, that the initial author of the file no longer has much meaning.
Furthermore, this will encourage developers to post to the developer group, rather than emailing Googlers (usually me) directly.
* Add annotations to files under core/events
* Add annotations to files under core/interfaces
* Add annotations to files under core/keyboard_nav
* Add annotations to files under core/renderers
* Add annotations to files under core/serialization
* Add annotations to files under core/theme
* Add annotations to files under core/toolbox
* Add annotations to files under core/utils
* Add annotations to files under core
* Move Menu + MenuItem out of /core/components to /core
Blockly.Menu and Blockly.MenuItem no longer depend on Blockly.Component and thus should not be in /core/component.
Also delete Blockly.utils.uiMenu in the process.