Update node-sass dependency

[evanfuture]

There is an issue with watchers in the latest version of node-sass. This fixes us to to the last version that worked. Fixes issue #47

[vakrilov]

Thanks @evanfuture!

[datanotion]

This was driving me crazy - I must have been running an older version, as it seems to work now.

As a side note, this issue was fixed 2 days ago in node-sass: https://github.com/sass/node-sass/pull/2151/files

Question though - nativescript-dev-sass still seems to be transferring the .sass file to the device as well - is that what is causing the app to restart even on style changes?

[evanfuture]

I'll keep an eye on that fix, and make another PR here to bump the version once it's out of pre-release (4.7.0) and I test it out of course.

I don't know about the sass files, but yes, that would trigger a restart. I thought I read somewhere that it would be nice to not have them transfer, but no one had the time to take that up. Not sure!

[evanfuture]

Ok, checked it out and made a PR: #51 Works well!