Removal of function types

[Stephen Colebourne]

The latest (6 July) lambda document removes function types. I support
this (even though they were in FCM).

- Removing them reduces the scope, thus increasing the delivery likelihood
- Function types look pig ugly with exception transparancy
- Function types are a very different concept to the rest of Java,
which is very name based
- Function type don't visually look much like types (which are names
everywhere else)
- SAMs centralise the definition of Javadoc and give a meaningful name
- function types don't
- Function types were causing trouble when in a list/array due to
generic erasure
- Removing them removes some of the most contentious syntax debates
- Function types can be added later if the right approach is taken (as
in the doc) of declaring lambda expressions to have no expressible
type.

I suggest using this thread to comment on the removal of function types :-)

Stephen