Support long tap gesture

[sunnyyoung]

Support long tap gesture in order to share or save the image.

[DreamingInBinary]

I think for this one we could possibly just show the UIActivityViewController - any thoughts you have on this one @ay8s 😄?

[ay8s]

👍 Sounds good to me to show UIActivityViewController and ensure we include actions to copy, save etc.

[DreamingInBinary]

Merged in here 👍