Async converted to sync

[designstorming]

When dealing with large number of files (scss) which are deeply nested, readFirstFile simply halts after 4th file. Probably, it opens the same file twice and it halts at second file until it's closed (which never happens, for me, for unknown reason). Anyway, it's converted into readFileSync

[xzyfer]

This is due to a known node-sass issue due to a libuv (node) limitation. sass/node-sass#857

The official work around is to set process.env.UV_THREADPOOL_SIZE to value > 4.

I suggest add the following to the file calling node-sass.

process.env.UV_THREADPOOL_SIZE = Math.ceil(Math.max(4, require('os').cpus().length * 1.5));