Improve bundle show -V

While bouncing around ideas for a Bundler related tool I thought that `bundle show -V` could do with some extra info, so I quickly hacked something together. The new output looks like this:

```
  * activesupport (4.1.1)
	Summary:  A toolkit of support libraries and Ruby core extensions extracted from the Rails framework.
	Homepage: http://www.rubyonrails.org
	Status:   Outdated - 4.1.1 < 4.1.4
  * awesome_print (1.2.0)
	Summary:  Pretty print Ruby objects with proper indentation and colors
	Homepage: http://github.com/michaeldv/awesome_print
	Status:   Up to date
```

It includes everything `bundle show -V` included so far, as well as the homepage and output similar to `bundle outdated`. I think this could be especially useful when you start working on an already existing projects to quickly get an idea which gems are involved, how up to date the overall project seems to be etc.