Pin node-sass version to 3.4.2
Pin node-sass version to 3.4.2

Fix #278

More info can be found here:
https://github.com/sass/node-sass/issues/1474

corani/beancount-web,yagebu/fava,corani/beancount-web,yagebu/fava,beancount/fava,yagebu/fava,aumayr/beancount-web,yagebu/fava,aumayr/beancount-web,beancount/fava,beancount/fava,corani/beancount-web,aumayr/beancount-web,corani/beancount-web,aumayr/beancount-web,beancount/fava,beancount/fava,yagebu/fava