Add method to modify exif data

[stackcoder]

Expose the vips_image_set, vips_image_get functions to the go world.

[tonimelisma]

Hey @stackcoder thanks for opening the issue. Can you clarify whether this is a feature request or whether you'd be up for creating a PR yourself? There's several other recent pull requests which expose new vips functions in an idiomatic way, they should provide good examples if you have the time.

[stackcoder]

It's only a feature request right now. I was looking for something like the withMetadata of sharp.

[AttilaTheFun]

@tonimelisma @stackcoder +1 on this - I'd love to be able to read and write EXIF data with this library as well.

[tonimelisma]

I feel like EXIF data manipulation is a bit outside of the functionality libvips has. Thus I'd deem it also outside the scope of govips. I'm sure there are other golang libraries to manipulate EXIF data, even though I understand that it would be useful to have the functionality in the same library.

[AttilaTheFun]

@tonimelisma that's totally fine -- now that I have the APIs to extract blobs, I'm pulling out the EXIF and XMP data and using other libraries to parse that.