Add getImage() to the ImageCache interface in the API.

Thus making it approximately infinity% easier to access image data of
acquisitions where the images were not initially added by the user.

git-svn-id: https://valelab.ucsf.edu/svn/micromanager2/trunk@14393 d0ab736e-dc22-4aeb-8dc9-08def0aa14fd
ASITiger: added refreshProperties property to LED (other devices have it)

git-svn-id: https://valelab.ucsf.edu/svn/micromanager2/trunk@14394 d0ab736e-dc22-4aeb-8dc9-08def0aa14fd
SimpleAutofocus: Fix crash on unloading w/o initializing

git-svn-id: https://valelab.ucsf.edu/svn/micromanager2/trunk@14395 d0ab736e-dc22-4aeb-8dc9-08def0aa14fd