Make line + point 1 trace instead of 2
Adapt existing test to expected output with merged traces
Handle exceptions in comparing trace names and favour markers over lines
Include line info in new one trace inherited from markers trace
Take the union of the 2 original traces instead of favouring markers
Merge branch 'master' into marianne-merge-layersintotraces
Update version number
Merge pull request #146 from ropensci/marianne-merge-layersintotraces

Little hack to make layers geom_line + geom_point 1 trace in Plotly