Is this guy flirting wit me? HElP!?

Okay, so I really like this guy in my english cl. his name is Jason. anyways on the first day of cl he boldly asked what my name is and i told him. then he pulled back my chair when i was working. one day I asked him if he had any weird talents and he told me to give him my hand. so i did and he held my hand and popped a bone in my hand. ive dropped hints that i like him by smiling but i cant tell if he likes me. one day he played with my hair and i jokingly told him to stop. i give him gum in cl and the other day i saw out of the corner of my eye him staring @ me for awaile. so i looked at him back and said "yes?" then he scooted his chair next to me and asked for gum. in the library he stole my library book (which was in my hand) and i fought with him to get it back (playfully) then he threw the book @ my . he also often takes my cell phone from me. is this guy flirting with me? I have no idea and i need to know if he likes me and if so what other signs i can pick up to determine if hes into me. Thx!