Fixed encoding/decoding on python3

The whole point of Ceedling (and the reason I'm working on Rake is to get Ceedling ST3 compatible), is to do TDD in C, but I haven't a clue how to do TDD on Sublime plugins. "Testing" at this point is just navigating to a file that has a rakefile in its folder and running the rake command to see what happens. As a result, I am certain there are more bugs, but this works as well as I can tell on my Ceedling project on my Windows XP machine using ST3. I need to get ST2 installed to compare the results and make sure nothing is broken. Thanks for accepting my previous pull request. This fix should get us closer to having a fully automated Ceedling environment in ST3.