Put core activity actions in the same place across activities

[sj]

From teacher feedback

* Core activity features should always show up in the same place in an activity... ==> being able to launch without the core "activity-tab" buttons available is repeatedly confusing.

This means, among other things : have certain features (closing an activity, changing sharing status) always available with the same set of keystrokes/movements, not requiring opening a special tab. This is made worse by activities choosing different default tabs.

[Eben]

This is a tough one. The choice to omit a static, persistent toolbar for meta actions (keep, stop, etc.) was made to preserve space, as well as to give the activity the top edge of the screen (for easier buttons to hit, along the edge. With this decision, many found it confusing, for instance, to open Browse and not have an address bar immediately presented; or paint and not see the painting tools. For this reason, we recommended that the default toolbar be chosen by the activity, which I still think is the right choice.

There are two improvements to the system that I think are relevant to this issue:

1. We're going to add "encouragement" for naming/tagging of activities in an upcoming release, which should reduce the need to have input focus on the title entry. This doesn't solve the problem for things like stop and keep, though keep at least should be 99% automatic.

2. The new toolbar proposal (http://wiki.laptop.org/go/Designs/Toolbars) can provide a great way to handle this problem, since the activity toolbar would become a toolbar button in the new paradigm, and could be shown in addition to the default activity toolbar. This makes the meta actions persistently available for as long as the kid wishes them to be, though they may hide them as desired.