Add stripdeclarations option

[malthejorgensen]

Add the option stripdeclarions to the loader.
If given will tell the loader to strip out any XML declaration, e.g.

<?xml version="1.0" encoding="UTF-8"?>

at the beginning of imported SVGs.

Added because Internet Explorer (tested in Edge 14) cannot handle XML
declarations in CSS data URLs (content: url("data:image/svg...")).

[codecov]

Codecov Report

Merging #102 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master   #102   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           1      1           
  Lines          18     20    +2     
  Branches        4      5    +1     
=====================================
+ Hits           18     20    +2

Impacted Files	Coverage Δ
index.js	100% <100%> (ø)	⬆️

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[bhovhannes]

Internet Explorer (tested in Edge 14) cannot handle XML
declarations in CSS data URLs

Is it documented somewhere? It will be nice to put a link about that in a README.

Otherwise this looks good for me. Thank you!

[malthejorgensen]

Can't find it anywhere, I was hoping caniuse would have it.
And apparently it only happens in Edge (not in IE 11).

Screenshots:
https://www.browserstack.com/screenshots/1ec164d16c5fffe93b88699b21158d1f618fff02

Codepen:
https://codepen.io/malthejorgensen/full/MooKQe/

[bhovhannes]

@malthejorgensen, I also found nothing about support, but the screenshot perfectly shows that removing xml declaration indeed fixes icon under Edge.
Maybe it makes sense to always strip xml declaration? Do we need it for other browsers?

[malthejorgensen]

I don't know, you could be right – that it's a better default to always remove the declaration.

I don't really have a good basis to make the decision on – I do like the ability to turn it off though. Most examples (if not all I've seen) do not include the XML declaration, however I don't know if it has any implication on e.g. encoding (which can be specified in the declaration)

[bhovhannes]

@malthejorgensen , I am opening a separate issue (#104) about making stripdeclaration the default behavior of the loader.
Your changes are released in version 2.1.0