Lucian Sava got the fundamentals right, "totes" is basically a shortening of "totally". But there is another thing to keep in mind, "totes" is a slang word, so it has a lot of implied meaning on top of it's literal definition.
It depends on the age really (from what I've seen). A lot of teenagers and people in their early 20's simply use "totes" to add emphasis to the word that follows it. So, "that book is totes awesome" would translate as "that book is extremely awesome".
It gets a bit more complex when you get to the (slightly) older generation, about 23 ~ 35. I think we've all taken to making fun of people who use "totes" as mentioned above. So when we say "totes" we usually mean it in a sarcastic fashion. So, if I were to say, "that book is totes awesome" I would probably mean, "that book would only be good if I were a shallow teenager." Though I don't always use it in such a mean way, I have before, and I have a lot of friends who do.
In other cases, I have seen people use it simply to add some silliness/humor to what they are saying. "I totes love broccoli, it's my hero!" said in the right context may simply mean the speaker is trying to add a certain degree of humor or silliness to their statement.
Point being, the word is "idiomatic slang", so you need to be careful when you see it used. It could simply be being used for emphasis or, possibly, it is being used sarcastically. Like all social idioms, pay close attention to the context in which the word is used and you should be fine.