Add shutter mode and mechanical shutter count to nikon makernote 3

[hassec]

These were easy enough to add, and I figured they might be useful.

Added a quick test based on the Nikon z6 file (CH0_0174.exv) that is already in the repo to test the version 8 lens data.

[clanmills]

Thanks @hassec. A couple of comments:

1. Do we need print0x0034? There's a macro to match values to string definitions for prettyPrinters. I think expects the value to be an index. However it would be nice to have a variant of that in which the value value is a key to a sparse vector of strings. We might be able to use that to simplify lots of pretty printers. What do you think?

2. You can put more than one test into a python script. Have a look at test_issue_981.py You can almost certainly add the test from tests/bugfixes/github/test_pr_1444.py to tests/bugfixes/github/test_pr_1437.py. And that makes sense because this PR is really a supplement to Implement Nikon LensData version 8 handler (0.27->master) #1437.

[clanmills]

Have a look at nikonFlashComp. Its a TagDetails array, which is a sparse array of value/strings. Can you use something similar to eliminate the need for print0x0034?

[hassec]

Thanks for the quick review @clanmills :)

I've moved the test into the one you suggested.

Re print0x0034, I'm not sure what would be best. As you already said, the EXV_PRINT_TAG macro unfortunately won't work for this without modification.
That's why I just went along with the style of the file and created another printXYZ function.
I think for this particular case it makes for a compact PR that can't really break anything existing.
If it was up to me I'd leave a larger refactoring of the overall printing functionality for a new PR that can target master and use C++11.

Edit: had misunderstood EXV_PRINT_TAG

[clanmills]

You're right. We shouldn't do a big edit on working code.

However, if you can get things to work with a TagDetails array instead of print0x0034() I would much prefer this.

[hassec]

Thanks for the suggestion @clanmills! I updated my comment above, I had actually misunderstood the macro.

Just adapted to code accordingly. It's now even shorter and thus nicer ;)

[clanmills]

Good Job. Very nice job.

Very clever of you to add the extra -g shutter/i stuff to the existing test. Less is always more in software.

[clanmills]

When the CI is green, please merge.

[hassec]

@clanmills I don't have the rights to merge

[clanmills]

Let me look at the permissions. You're obviously a very good engineer. I'm happy for you to merge.

[clanmills]

I thought I added you last week. Anyway, you should be in now.

When you want to submit a PR in future, can you create it in the exiv2/exiv2 repos. Much easier work-flow. Other team members can edit/update it. And easier for me to sync/build/review.

[hassec]

Awesome! Thanks a lot, it's much appreciated 👍