EEP 23 implemented

[Björn Gustavsson]

I have updated this branch:

git fetch git://github.com/bjorng/otp.git bg/external-funs


I have removed the attempt to help Dialyzer analyze
external funs better. Instead I have documented
erlang:make_fun/3. The reason is explained in
this commit:

http://github.com/bjorng/otp/commit/4a3bc9f9ebd31dc092dcccbfc21cdd9cca6af6c9

-- 
Björn Gustavsson, Erlang/OTP, Ericsson AB