reduced silly excess (empty) comment lines
Added some of the basic generator combinators

I'm actually not specifically sure if it's okay, but I modified
the behaviour of the 'vector-of' function. In haskell, this function
simply returns a list of a given length. However, in scheme (and lisp
in general I guess), vectors and lists are separate datatypes.
Since vectors mean something specific in scheme, I opted to return
what you would expect (a vector object a la #< a b c>) as opposed
to what haskell would do. At the end of the day this library is meant
to be quickcheck-like, not a 1:1 clone, so I justify this choice on
the grounds that the library should be written as if it's going to
be used as scheme code, not as if it is haskell code with scheme
calls.