Add rstudio project
Respect text/graphics callbacks in new_output_handler
Bump version
Update news
Only call graphics handler when there is graphical output to process
Merge pull request #43 from takluyver/graphics-handler-notnull

Only call graphics handler when there is graphical output to process
Add test for graphics output handler
Use file=NULL to avoid writing files for graphics
Add test that Rplots.pdf is not created

This test fails if I revert the previous commit.
Clean up test
Only pass file=NULL if default device is pdf
Merge pull request #44 from takluyver/dev-file-null

Avoid creating Rplots files
I just use the normal R CMD build/check, but I'm okay if devtools is preferred
fixed a bug related to multiple expressions on the same line, reported by Bill Venables

the real change is from `if (!is.null(call))` to `for (expr in call)`; the rest of changes are basically further indenting the code
closes #42: append \n to all comment lines except the last line when the whole block of code only consists of comments
clean up the old tricks to get rid of Rplots.pdf after #44
merge the test from test-graphics-nofile.r to test-graphics.r after #44
bump version