Modify EInotebook ratings so they are appended to ratings file dynamically

[jdalbey]

The current EInotebook has a preliminary version of ratings that uses a Submit button at the end of the page to save the ratings. The two obvious shortcomings are

1. If the browser is closed before submitting all the ratings are lost.
2. If multiple browsers are open only the last person to change a rating is saved.

This ticket specifies a modification to address these issues.

1. Create a new python script in the cgi-bin folder that will append a single rating to the ratings file.
2. In Evaluation.js create a new function to write a rating (by calling the python script) given a rating, that will write the time, rating, and eval type.
3. Modify LoadEvents to include event time in constructor to Evaluation (2 places)
4. Add event time to constructor for Evaluation
5. Modify smallScaleForm() to call writeRating instead of recordRating

[jdalbey]

Implemented in #631, #632

[jdalbey]

implemented in r631, r632