utilrb version 1.3 has been released!

## What is Utilrb ?
Utilrb is yet another Ruby toolkit, in the spirit of facets. It includes all
the standard class extensions I use in my own projects like Genom.rb.

## Installation
The only dependency Utilrb has is flexmock if you want to run tests. It is
available as a gem, so you can run

gem install flexmock

## Utilrb's C extension
Utilrb includes a C extension in ext/. It is optional, but some of the
functionalities will be disabled if it is not present. Trying to require
a file in which there is a C-only feature will yield a warning on STDOUT.

Changes:

### Version 1.3

* added Utilrb::WeakRef, a much leaner version of the standard WeakRef:
implemented in C++, not a subclass of Delegate (delegate is very costly)