Fixes #100 #99

All be it a temporary solution, I definitely need this soon.

How and where in webpack should I use renderSync?

If you'd like to try my fork with these fixes, you can do npm install github.com:OpenLearningNet/sass-loader.git --save. That means instead of using the main branch of sass-loader you use my branch which is the source of this pull request. Otherwise if this or another fix gets merged you can go back to jtangelder's branch.

@hedgepigdaniel tried your solution but it only delays the hanging from 40% to 61% for me, so not a complete fix unfortunately

Mhmmm ... do you know how deasync works? I'm a bit afraid to merge this when deasync is messing with node's event loop. It looks like black magic to me 😀

Can more people try this PR locally? If it fixes the current issues (and deasync is "harmless"), I am willing to merge it.

Issue fixed by #132.

But thank you for your effort and your proposal 👍. Although I did not merge it, I do think that these contributions help to improve the code.