Removed the unused jQuery parameter
Removed unused function wrapper
Extended the async init method to plugins. (Among other things.)

Tasks:
 - Allow creation of "floating" (manager-less) instances,
   and adding the to a TaskManager later. (Required for plugins.)
 - Added the failed() method, to signal failure. This is cascaded to dependant tasks, too.
 - Added protection against accidentally calling resolve() or reject()
   (instead of the intended ready() and failed() methods)
 - Added protection against calling the ready() and failed() methods outside pending state
 - setDeps now copies array, instead of referencing it.
 - TaskManager now supports automatically adding progress callbacks to all tasks
 - bugfixes: actually set @started, don't try to schedule an already started task

Annotator:
 - Documented the user options for constructor
 - Initiation of the d-t-m libraries is no longer optional; it's now done in
   the constructor. (Rationale: earlier, it was optional for two reason:
   1. The libraries may not be available 2. Instantiating them might be slow.
   Neither of these reasons are true any more; the libraries are now compiled into
   annotator.js, and their constructors are very cheap.)
 - Added default logger callback to all tasks
 - Simplified task names
 - Implemented async plugin loading.
   This is triggered automatically when the init process was run in Async mode.
   In sync mode, everything happens as it used to.
   In async mode, if the plugin has a dedicated init task defined, then it's scheduled.
   (Dependencies are supported, specified both in the code of the plugin, and
   at the options of the loadPlugin call.)
   If no dedicated init task is defined, then the sync initPlugin method is wrapped
   into a task.

Auth plugin:
 - Implemented async init task, which is resolved/rejected according to the results
   of the call made to the token server.
 - The withToken method (to register callbacks) is no longer supported in Async mode.
   (Dependencies should be used instead.)

Permissions plugin:
 - Declared dependencies. (Used for async plugin loading.)

Store plugin:
 - Implemented async init task, which is resolved/rejected according to the results
   of the call made to the backend.

dev.html:
 - Reverted to earlier, sync form. (With simplifications from original.)

dev_async.html:
 - This is the new, async version of dev.html, which
   showcases async, dependency-managed init process and plugin loading.