The layout issue was related to the lack of autoprexing for CSS
properties. c69f993 did improve the reload time significantly but for
that I had to replace `mquandalle:stylus` by the core `stylus`
package. Unfortunatly it is currently difficult to run an autoprefixer
with the core CSS compilers (as reported in
https://github.com/meteor/meteor/issues/5219).
So instead we rely on `nib` which transparently define some mixins for
autoprefixing, the only restrictions being that we have to manually
`@import 'nib'` on top of stylus files.
Fixes#461
