tutorial: Remove the entire 'Types' section

It's not interesting

/cc: #4217

doc/tutorial.md

@@ -308,87 +308,6 @@ fn is_four(x: int) -> bool {
 }
 ~~~~
 
-## Types
-
-The basic types include the usual boolean, integral, and floating-point types.
-
-------------------------- -----------------------------------------------
-`()`                      Unit, the type that has only a single value
-`bool`                    Boolean type, with values `true` and `false`
-`int`, `uint`             Machine-pointer-sized signed and unsigned integers
-`i8`, `i16`, `i32`, `i64` Signed integers with a specific size (in bits)
-`u8`, `u16`, `u32`, `u64` Unsigned integers with a specific size
-`float`                   The largest floating-point type efficiently supported on the target machine
-`f32`, `f64`              Floating-point types with a specific size
-`char`                    A Unicode character (32 bits)
-------------------------- -----------------------------------------------
-
-These can be combined in composite types, which will be described in
-more detail later on (the `T`s here stand for any other type,
-while N should be a literal number):
-
-------------------------- -----------------------------------------------
-`[T * N]`                 Vector (like an array in other languages) with N elements
-`(T1, T2)`                Tuple type; any arity above 1 is supported
-`&T`, `~T`, `@T`          [Pointer types](#boxes-and-pointers)
-------------------------- -----------------------------------------------
-
-Some types can only be manipulated by pointer, never directly. For instance,
-you cannot refer to a string (`str`); instead you refer to a pointer to a
-string (`@str`, `~str`, or `&str`). These *dynamically-sized* types consist
-of:
-
-------------------------- -----------------------------------------------
-`fn(a: T1, b: T2) -> T3`  Function types
-`str`                     String type (in UTF-8)
-`[T]`                     Vector with unknown size (also called a slice)
-`[mut T]`                 Mutable vector with unknown size
-------------------------- -----------------------------------------------
-
-> ***Note***: In the future, mutability for vectors may be defined by
-> the slot that contains the vector, not the type of the vector itself,
-> deprecating [mut T] syntax.
-
-In function types, the return type is specified with an arrow, as in
-the type `fn() -> bool` or the function declaration `fn foo() -> bool
-{ }`.  For functions that do not return a meaningful value, you can
-optionally write `-> ()`, but usually the return annotation is simply
-left off, as in `fn main() { ... }`.
-
-Types can be given names or aliases with `type` declarations:
-
-~~~~
-type MonsterSize = uint;
-~~~~
-
-This will provide a synonym, `MonsterSize`, for unsigned integers. It will not
-actually create a new, incompatible type—`MonsterSize` and `uint` can be used
-interchangeably, and using one where the other is expected is not a type
-error. In that sense, types declared with `type` are *structural*: their
-meaning follows from their structure, and their names are irrelevant in the
-type system.
-
-Sometimes, you want your data types to be *nominal* instead of structural: you
-want their name to be part of their meaning, so that types with the same
-structure but different names are not interchangeable. Rust has two ways to
-create nominal data types: `struct` and `enum`. They're described in more
-detail below, but they look like this:
-
-~~~~
-enum HidingPlaces {
-   Closet(uint),
-   UnderTheBed(uint)
-}
-
-struct HeroicBabysitter {
-   bedtime_stories: uint,
-   sharpened_stakes: uint
-}
-
-struct BabysitterSize(uint);  // a single-variant struct
-enum MonsterSize = uint;      // a single-variant enum
-~~~~
-
 ## Literals
 
 Integers can be written in decimal (`144`), hexadecimal (`0x90`), or