Added option 'emitWarnings' to identify unprocessed files

[Root-Core]

Hello there,

as we have two options, which will prevent processing of files, we should have an option to identify these unprocessed files.

You might consider to default this to true or warn without the option, as it should be useful in most cases.
I could do this, if you give me some feedback. 👍

Regards!

[codecov]

Codecov Report

Merging #150 into master will decrease coverage by 6.25%.
The diff coverage is 60%.

@@            Coverage Diff             @@
##           master     #150      +/-   ##
==========================================
- Coverage     100%   93.75%   -6.25%     
==========================================
  Files           1        1              
  Lines          28       32       +4     
  Branches       10       12       +2     
==========================================
+ Hits           28       30       +2     
- Misses          0        2       +2

Impacted Files	Coverage Δ
index.js	93.75% <60%> (-6.25%)	⬇️

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[bhovhannes]

Thanks for your PR!

Code looks great. Can you add some tests to make codecov happy?

Also I am curious if it is possible to see the name of the file in the warning message. Message will be much more informative if it will contain the name of the file for which svg-url-loader felt back to file-loader.

[Root-Core]

I can look into it, tough I dont't really know how this could be tested.

The file name seems to be unavailable and not necessary too, as webpack shows warnings emited via this.emitWarning() straight under the regarding file name + some additional info.
At least it had done it for me, while testing this. I could provide screenshots if you want.

[bhovhannes]

@Root-Core , then add some tests and I'll be happy to merge your PR.

Regarding tests. Perhaps it will be possible to setup a spy on emitWarning() method.