Add high resolution iOS photo capture for file

[Maleandr]

Added high resolution support for image file saving in iOS.

[googlebot]

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[Maleandr]

I signed it!

[Hixie]

cc @xster for review

[Hixie]

@Maleandr looks like the clabot wasn't satisfied by your signature? Not sure what's up, can you check to make sure you signed it with the same github account then comment here again? Thanks.

[Maleandr]

I signed it via corporate agreement and added my email later. Is this causing issue? I see valid CLA corporate agreement on https://cla.developers.google.com/clas

[googlebot]

CLAs look good, thanks!

[Hixie]

ping @xster

[xster]

Seems reasonable. LGTM.

Please make sure this change is versioned.

Add an entry to packages/camera/CHANGELOG.md and change the version number in packages/camera/pubspec.yaml to 0.2.2.

[xster]

I restarted the tests

[xster]

Not sure why these tests on Cirrus are failing when it passes on Travis. Can you rebase your 2 commits on head and push again?

[Maleandr]

Rebased

[xster]

Thanks for your contribution. Merging.