Add new equation ops

[bnorthan]

Add ops for calibrated equations (AbstractCalibratedEquation.java), equations passed in using an op (DefaultCalibratedEquation.java), and equations passed in using a binary lambda
(DefaultXYCalibratedEquation.java).

This allows me to implement equations fairly easily. For example:

// define origin and calibration
double[] origin = new double[] { -1., -1. };
double[] calibration = new double[]{0.1,0.1};

ops.image().equation(image, (x, y) -> Math.pow(x, 2) + Math.pow(y, 2),
            origin, calibration);

or (since origin and calibration are optional)

ops.image().equation(image, (x, y) -> 10 * (Math.cos(0.3 * x) + Math.sin(
            0.3 * y)));

[bnorthan]

@ctrueden, @dietzc let me know your thoughts. Some of the code is a little tricky. I am happy to consider changes to design. I just need a concise way to implement a calibrated equation.

[ctrueden]

That is hot! Will review after I return home from traveling. Or @dietzc feel free to merge sooner if you like it!

[dietzc]

several format changes in this file make it hard to review the actual changes. can you undo the format changes and commit only thing related to the functionality you added/changed? I know it's a bit annoying, but it helps in the long run :-)

[dietzc]

I added some comments about the coding style itself, but didn't have time to check the actual functionality in detail. maybe @ctrueden can quickly do that.

[ctrueden]

Sorry, some urgent priorities have come up. I will not have time to look at this for some weeks now.

[dietzc]

I suggest to wait with the merge until we finally decided how we represent calibrated images in the future.

[ctrueden]

Closed in favor of #531, as suggested by @bnorthan.