Clean out old style definitions when live testing

[bfulop]

During live testing, at each keystroke aphrodite adds a new CSS definition to <styles>.

Old styles could be removed, but it has to be done through Inferno. If I revert the state of my CSS Aphrodite/Inferno will not add a new element but reuses the old style. So this has to be done with care...

[bfulop]

Probably the safest way to do this is the issue a browser refresh command periodically.

[bfulop]

https://github.com/segmentio/nightmare refresh after n run...