Use stdin and stdout#4

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aostroukhov wants to merge 14 commits intosshmyg:masterfrom

Commits on Oct 17, 2016

Commits on Aug 1, 2017

unstable vendor mixin detection disabled by default;
mborik
committed

Commits on Aug 15, 2017

Commits on Sep 20, 2017

implemented algorithm to keep comments of rules/properties in their position and reformat
mborik
committed

Commits on Sep 21, 2017

fixed rules with just comment inside
mborik
committed

Commits on Sep 22, 2017

Commits on Sep 28, 2017

final touches and sequential file processing with Promises
mborik
committed

Commits on Oct 3, 2017

fixed relative urls and implemeted advanced path relativizer for absolute server urls
mborik
committed

Commits on Oct 9, 2017

bugfixes
mborik
committed