Added SimpleCove and Selenium to test with JavaScript

Hi Jaak,

I've added SimpleCov to find out what is not covered.
To test with Javascript I've added 'Selenium'

When you've merged this pull-request do the following:

* git pull
* bundle # to install new gems - selenium will compile C-extensions, hopefully this works without troubles on your mac. Otherwise we can check it tomorrow.
* rspec -f d spec/
* open coverage/index.html

I've added specs for adding a new entry, just to see if selenium works, but I left 12 uncovered lines for you ;-)

cu 2morrow