Gulpfile updates

No changes to the source code this time... The default gulp task used to finish minifying the css before compiling the sass, and I therefore had to always run the gulp command twice. This is now fixed thanks to the package. The gulp command now outputs:

[12:00:25] Using gulpfile ~\Documents\GitHub\waffle-grid\gulpfile.js
[12:00:25] Starting 'default'...
[12:00:25] Starting 'sass:compile'...
[12:00:25] Finished 'default' after 176 ms
[12:00:26] Finished 'sass:compile' after 1.49 s
[12:00:26] Starting 'css:minify'...
[12:00:27] Finished 'css:minify' after 282 ms

This means that the travis file only runs one command, instead of gulp sass:compile and then gulp css:minify.

That's it!!