Adds support for SVG sprites

[pmpinto]

Hey @stkao05!

Here's the update that generates SVG sprites.
As you may know, this is only my second time messing with gulp tasks, so please let me know if there's anything that could/should be improved 😊 👍

[pmpinto]

This is the shameless part of this whole process... I looked for a node package that would generate svg sprites, work with gulp and would export css out of a handlebars template.

This dr-svg-sprites was it. But it turns out it also exports a PNG fallback that we are not really using and I don't think we need that. The worst part about that, is that there's no config option to turn it off, it will always export the PNG file.

So these 2 lines (88—89) are there only to get rid of the file 😅
It works, but I'm not particularly proud of it...

[stkao05]

Hi Pedro,

I will close the pull request first since the code works. But keeps in mind that there are things which I think could be improved.

• When you add new dependency to the project, please also update package.json.
• I think gulp-svg-sprite might be a more promising SVG sprite since it provides versatile svg sprite option. With dr-svg-sprites we are limited to using svg sprite as background image.
• I also think it might be better to make svg sprite as a completely separated tasks svg-sprite since svg sprite could potentially take much different configuration option than png sprite.

[pmpinto]

Making it a whole new task actually makes a lot of sense! I should have thought about it when I felt so many friction points when adapting the existing task to support SVG.

I will add this as a task to move from dr-svg-sprites to gulp-svg-sprite. And also create a new separate task to handle the job.

Thanks so much, Steven 👍