Add travis config
Add build status image to readme
Add python 3.4 to travis build
Also install pandoc
Merge pull request #5 from jhamrick/add-travis-config

Add travis config
Add nbgrader create assignment extension
Add example notebook to test toolbar
Ignore ipython checkpoints
Rename "autograder" cells to "test" cells
Update toolbar to only have 'solution' and 'grade' cells
Update example notebook
Only color grade cells when toolbar is active
Use booleans for grade and solution, rather than cell_type
Remove check for disable_nbgrader_toolbar
Only add the toolbar to code and markdown cells
Make extension a little more efficient
Don't modify resizable ui css
Use require to get URL for css
Change points text box to number type
Use checkbox ui generator for solution checkbox