strings as variable names for ggplot implementation

[swihart]

If I remember correctly, the thing holding up the ggplot implemenation was passing the strings
and then recognizing them as variable names. This worked for you in another project:

When trying to convert a paste string into a variable, eval(as.name(paste())) worked for me, thanks!

From the comments of:
http://stackoverflow.com/a/9057793/2727349