Method workspace identifier auto-completion can be more scope aware

[blairmcg]

• When assembling the list of identifiers we visit the scopes to find all the declared args and temps. This should take account of the scope at the insertion point and not add locals defined for other blocks in the method.
• Environment Browser should only include static variables that are part of the environment so that, for example, when browsing the content of a deployed application if editing takes place the auto-completion offerings are scoped to the classes/variables that survived into the app. Previous work limited the message completion lists to messages defined in the app.