[Scenario] Add model for power/comm costs

Add class to contain model for power and
communications cost. This will be used to
store the persistent state of Activity
Type components, as described in
nasa/MCT-Plugins#97
[Scenario] Define Activity Type component

Initial defition of the activity type
user object.
[Scenario] Support persistence of Activity Type
[Scenario] Class comment for activity type
[Scenario] Expose activity type via provider
[Scenario] Add general-use cost property editor
[Scenario] Display correct value in cost editor
[Scenario] Adjust info view fields in Activity

Change info view fields in activity to
remove Activity Type, and to use
power/comm property editors from
superclass.
[Scenario] Remove unused property editors

Power and Comms are both now handled by
CostPropertyEditor, so their specific
property editors are no longer needed.
[Scenario] Clarify tag repository

Report TagCapability, as opposed to
TagComponent, as the capability aggregated
by tag repository. This is more accurate
to the intent of the getCapabilityClass
method (as described in method documentation)
[Scenario] Generalize repo containment rule
[Scenario] Decouple ActivityVisualControl from tags

Remove explicit references to TagCapability and
TagComponent from ActivityVisualControl. This is
to permit subsequent reuse of the same UI for
Activity Type specification.
[Scenario] Suppress warning (not applicable)
[Scenario] Add bootstrap type repositories

Add Activity Type repositories as top-level
(bootstrap) components, similar to
Tag repositories.
[Scenario] Group repositories by type
[Scenario] Remove internal costs from Activity

Do no expose internal cost functions from
activity, unless values are non-zero
(to maintain backwards compatibility with
cost-containing activities.)
[Scenario] Allow activity to contain activity type
[Scenario] Trim cost functions to activity duration
[Scenario] Show correct type names in dialog

Base the type names shown in the create
dialog triggered from an Activity's info
view on the type of object being created.
[Scenario] Show correct names in combo box

Base the type names shown in the combo
box in an Activity's info view on the
type of object being created.