Corrected some grammatical errors.

Hello Stefano, 
I looked at the first half of the readme  and corrected some grammatical errors. I also removed the "..." in the feature list because the list is long enough already and the dots just looked a bit messy. 

Further, I removed the controversial GUI from the to-do list! Mostly because I don't want a GUI, but also because the dots before the GUI item annoyed me and removing them made it even worse.