p -> py for r/ggplot2 sign_in. Throw exception when sign_in missing.

note, the p vs. py thing needs to be fixed in streambed as well.
update some script files with sign-in lines that were erring.
ran `python run.py process ggplot2` to update changes (not published).
removed "library(ggplot2)" (and trailing ws in these files)
Run ggplot2 scripts through to change auto-docs.
Merge pull request #34 from plotly/andrew-fix-gg-examples

Andrew fix gg examples