Allow different projection on overview map

[buehner]

I noticed that the overview map requires the same projection as the parent map.

This PR allows the overview map to use a projection that differs from the parent maps projection.

Changes basically include the transformation of coordinates/geoms, if necessary. To assure that the magnification mechanism also works initially, some effort was necessary (as resolutions had to be available on the overviewView).

Note: Tests are still missing. I'll soon try to add some.

[marcjansen]

Looking slick so far, nice job. I'll give this a proper review, once tests have been added.

[marcjansen]

Will you continue work on this, @buehner?

[buehner]

Since #225 extended the functionality of the overview map, i think this PR needs some adaptions now.

Could not get your drag feature work in combination with a different projection yet. I'll have a look at his now.

[buehner]

I adapted the code:

• the boxCenter will be transformed if necessary when it is dragged
• the box will rendered initially
• the updateBox function will be disabled during the drag (as it interferes sometimes with the dragging)

Unfortunately it is not so easy to transform the whole box geometry when it is dragged (maybe someone has a good idea how to do this), but the drag feature is still easy to use.

I'll try to add some tests now.

[marcjansen]

Still looks great. Once tests are there, I will have another look.

[chrismayer]

Any news here?

[buehner]

There are still some tests missing. I did not yet find the time to add them, but i'll try to add them as soon as possible

[buehner]

I added a test in e467ee0

[buehner]

The tests fail now due to the issue mentioned in #242

As soon as #242 is merged, i can rebase this one here to make it green!

[marcjansen]

LGTM. I'll merge once rebased.

[buehner]

I rebased! Now everything is green again...

[marcjansen]

Thanks again!