Clickable lifetime image

[grislis]

When a lifetime image is displayed it needs to be clickable.

Need to add a special tool to the toolbar, otherwise clicking on the image is ambiguous. (This is a problem with the IJ1 version.)

Generate and propagate a 'lifetime click' event.

In the default lifetime display mode clicking on the lifetime image in this special tool mode should pop up a graph showing the exponential decay data.

When the SLIM Plugin is running it should look for this event and fit on the clicked pixel. A graph showing the decay and fitted results should pop up (instead of the default decay graph).

Other lifetime fitting plugins could also use this UI. For instance this would be an ideal interface for the Time Gated Phasor plot IJ1 plugin at http://spechron.com/.

Added a plugin-specific click tool, created a specific lifetime one, and added the capability to hide/show tools. This is working for the Swing UI, but not other platforms. This work was done in the lifetime branch of imagej.

Currently the toolbar does not resize when you unhide (effectively add) the tool. For this to work properly I need to get the toolbar panel to resize or we could just have a fixed size with empty slots like IJ1.