changing parseInt to parseFloat so that non-int measurements don't get chopped off

This error occurred when using:
Then "post title" should have "font-size" of greater than "26px"

The problem was that 'post title' has a computed font-size of 26.6666px, but in the greater/less comparison, it does a parseInt which rounds that down to 26. I want to measure that the size is between 26 and 28, and so parseFloat allows me to do that. 

On a side note, I wasn't able to run the tests for some reason on my computer. Hopefully TravisCI doesn't have trouble.