The license update support is no longer limited to updating just the

information for the license being checked. Now, a license provider can

update the license information for multiple licenses at once when

returning a license payload, and can also remove licenses.
This enables a license provider to represent a main license with

multiple sub-licenses and then update or remove sub-licenses based on

the new license data, without having to do processing per-license.
To do this, the license provider's check license response now sets a

license_infos dictionary mapping license IDs to either payload data

(to add or update) or null (to remove). This is then handled on the

JavaScript side by updating all licenses from that provider that match

the ID.
Each license provider's set of licenses are managed client-side in a new

LicenseCollection, which performs those batch updates and also takes

care of performing a group of license update checks. These are now

checked sequentially instead of all at once.

Unit tests pass.
Tested this with the license support in Power Pack.