Adds Piwik tracking code.
Groups data/exclusions fields on coding form.
Updates Piwik code
Moves help buttons to the right of form fields
work on coding scheme
updated coding scheme; edited drop down choices and help text

Git asked if I wanted to add the test runner and other new things…I
just said yes because I had no idea if I needed them or not.
tutorial updated, formatting changes
scrollspy fixed, images fixed
changed headers
added feedback to tutorial
Ignores files generated by IDE
Merge Johanna's changes to the interactive tutorial
Merge branch 'develop'