[erlang-patches] Release the reltool script

[Håkan Mattsson]

With this patch the reltool script is released among the the other top
level executables, such as dialyzer, ct_run etc.
I did also take the liberty of enhancing the script and renaming it
script to "reltool".

A new test suite and a new man(1) page is included.

  git fetch git://github.com/hawk/otp.git hawk/reltool_script

or viewed here

  https://github.com/hawk/otp/compare/hawk/reltool_script
  https://github.com/hawk/otp/compare/hawk/reltool_script.patch

/Håkan