Starting a Bundle Asynchronously

When a bundle is started an instance of the bundle's activator is created and executed by the OSGi framework. The start up of a bundle's activator is therefore strictly synchronous. For the majority of bundles this is desirable, but for situations where a bundle's activator takes a long time to complete, executing on a separate thread is useful since it allows other bundles to continue to start.

SAT supports this need by providing a configuration parameter method for bundles that wish to have their activator executed on a separate thread.
By default the method isStartAsync() returns false to indicate that the bundle's activator should be started synchronously.
By overriding the isStartAsync() method to return true will cause the bundle's activator to start on a separate thread, for example:
```
protected boolean isStartAsync() {
  return true;
}
```
The method getAsyncStartPriority() returns the priority at which the thread used to asynchronously start the bundle will be run. By default this method returns Thread.NORM_PRIORITY, but may be overridden, for example:
```
protected int getAsyncStartPriority() {
  return Thread.NORM_PRIORITY + 1;
}
```