[Refresh] Add initial refresh button
[Refresh] Add button class for ContextAwareActions
[Refresh] Add refresh button to center pane

Complete nasa/mct#138 by adding a refresh button
to the center pane (in the title bar of the
content area). Triggers the Refresh Now action.
[Refresh] Unit test ContextAwareButton
[Refresh] Add refresh icon
[Refresh] Use component from persistence on refresh
[Refresh] Update refresh action test
Merge pull request #175 from VWoeltjen/mct138

[Refresh] Add refresh button to center pane, nasa/mct#138
[Refresh] Add refresh button to Inspector
[Refresh] Verify Inspector support in test
[Icons] Adjust look of settings/refresh icons

Adjust appearance of settings icon, refresh icon,
and switcher view to match more closely with
provided mock-ups and other specifications.
Specifically, add drop shadow to refresh and
settings and tweak alignment of these buttons
around the view switcher.
Merge pull request #177 from VWoeltjen/mct138

[Refresh] Add refresh button to inspector
[Icons] Remove more outdated icons
[Icons] Test ContextAwareButton's icon usage
[Icons] Remove menu icon from Refresh

Remove the SMALL_ICON key from RefreshAction;
this is used for menu items, but icon is only
desired for buttons (which use LARGE_ICON_KEY)
[Icons] Clean up commented-out code
Merge pull request #178 from VWoeltjen/mct138

[Icons] Tweak appearance to match mock-ups
[Database] Allow configuration of polling interval

Reduces database polling interval, and allows
configuration on a per-user basis. This addresses
both perceived and actual issues with object
modification:

* nasa/mct#54 notes that object deletion seems
  to take a long time. Root cause is that the
  Browse area is refreshed by database polling,
  which takes place at a longer interval (3s).
  Decreasing this interval means that the user
  sees the consequences of their action sooner.
* nasa/mct#132 occurs when the user switches
  back and forth between objects faster than
  the poll interval. This can cause an object
  to be flagged as stale because changes from
  one save have not made their way back to
  the Browse area. While this still may occur
  with a shorter polling interval, the odds
  of the user observing this decrease
  significantly.
* nasa/mct#111 describes latency issues, some
  of which may be related to the poll
  interval. (It is unlikely, however, that
  menu item latency is related to this.)
[Ownership] Prevent ownership change on bootstrap comps

In nasa/mct#123 the user is able to change ownership
of My Sandbox, which means they subsequently cannot
edit their own sandbox. Worse, when they restart MCT
they see no sandbox at all.

This adds a check to prevent this. When ownership
mutability is being determined, consult the list
of bootstrap components - this is the list of
components seen by the user in the User Environment.
Categorically disallow changes of ownership to any
of these (this includes both My Sandbox, and any
future top-level components introduced, as these
are presumed to be inherently tied to the user. An
example of a top-level component not yet introduced
is User Tags, described in nasa/MCT-Plugins#39.)
[Ownership] Consider bootstrap comps in unit test

Consider the case of bootstrap components in
unit test verifying whether or not ownership
change to a component is allowed.