Let line/path support shape aesthetic
Add test for geom_line() with shape aesthetic
Run image test for test-ggplot-path.R
Increment version number
Merge pull request #128 from ropensci/marianne-shape-support

Let line/path support `shape` aesthetic (i.e., symbols)
Use double quotes, not single quotes (see our Style Guide)
Merge branch 'master' of github.com:ropensci/plotly into add-r-cookbook-tests