update to scalaz 7.1.0

cross compile 2.10.4, 2.11.2
update library dependencies
fixed typos of function names
fixed type error by using sequenceU

there is still a type warning:
```
HttpResponse.scala:25: http.response.ResponseHeader and http.ContentType.type are unrelated: 
they will most likely never compare equal
[warn]     headers find { case (k, v) => k == ContentType } map (x => f(x._2)) getOrElse false
```
, but I do not fully understand yet, what they are supposed to compare.