Search Results: which kind of girls turn you off

There's this guy in my college class I've been friendly with (we mostly have small talk). He's super nice and friendly, and by friendly I mean he'll strike up a conversation with anybody and literally helps everyone who needs it (he jumped up and retreived a girl's pen during a test, helped a guy with his parking, and has helped me with the class several times). He also has complimented my appearance a few times, and I've noticed him glancing at me in class nearly every day.
When I learned he had a girlfriend (through Facebook), I immediately backed off because I liked him and didn't want to get attached or anything. However, about two weeks ago his status turned to "single." Since then, he's been more chatty with me. When we had to move seats in class (I didn't move) he immediately sat next to me. When I moved seats the next class time, he asked the girl next to him if we were supposed to (all while looking at me). Later on I was waiting for a tutoring session and he literally sat on the floor in front of me and helped me with some homework so I wouldn't be alone, and during class when we were supposed to talk about travel, he asked how my tutoring session went and how large my family was. Before an interview I had, he told me I should flirt because it'd help, which confused and amused me. And then, last week, as I was walking upstairs to class I realized he and this other guy I kind of have gotten to know were walking behind me. The guy I've gotten to know was walking super fast and skipping steps when I had starting walking faster, practically on my heels, while the guy I like was matching his pace and commenting how he was impressed with the other guy's speed. It was like a competition. Later on the guy I like saw me out in the parking lot and we had a friendly chat, but I haven't seen him since (he skipped class today).
I'm so confused because I can't tell whether he's being friendly or if he likes me.