Move property literals out of Plotly.restyle

See items 1, 2, 3 in https://github.com/plotly/plotly.js/pull/617#discussion_r67130816. 
Preceding comment from @etpinard: https://github.com/plotly/plotly.js/pull/617#discussion_r67041656
