Add mount device custom icon generation

[manrueda]

During the DMG generation (if gm is installed), a new icon will be created using the OS mounted drive icon and the apps icon. It will apply a perspective and size correction on the app icon before the composition.

Example:

Fixes #16

[sindresorhus]

You need to mention the gm install prerequisites in the readme if users want a DMG icon.

[sindresorhus]

This is looking great:

[sindresorhus]

Can you also set the icon on the DMG file itself?

[sindresorhus]

@manrueda Can you add commits instead of squashing and force pushing so I can see what changed? I will squash on merge anyway.

[manrueda]

Sure (its done).

About the icon for the dmg file. Looks like macos had all the right tools to do it, but they removed one time ago and not the only solution is some python script.

https://apple.stackexchange.com/questions/6901/how-can-i-change-a-file-or-folder-icon-using-the-terminal/161984#161984

[sindresorhus]

How about bundling the seticon binary here: https://github.com/sveinbjornt/osxiconutils ?

[sindresorhus]

You need to add the disk icon to files in package.json

[manrueda]

Disk icon added

[sindresorhus]

Any thoughts on #33 (comment) ?

[manrueda]

I can give it a try, i don't have much experience with releasing binaries on macOS. Because this library already only works on macOS for obvios reasons should be on to bundle the compiled binary, right?

[manrueda]

Just pushed an implementation of seticon binary.

[sindresorhus]

Works great! Thanks for doing this :)