block parameter changes for ruby 1.8.7

Hi, 

I was having problems on ruby 1.8.7 with lib/page-object/widgets.rb.  So I changed the default block parameter to make 1.8.7 work as well as 1.9.3. (Extending 1.8.7 support at least for a bit longer)  

Ran tests on both 1.9.3 and 1.8.7. All passed. 

Is 1.8.7 still officially supported? Let me know what you think.

Thanks