Change bundler dependency from ~>1.0.0 to ~>1.0

[gthiruva]

The bundler dependency needs to be updated to play nicely with the forthcoming bundler 1.1. Actually, I'm not sure if bundler even needs to be a dependency for this project. So maybe, the line can just be taken out entirely.

$ gem dependency -R bundler
Gem bundler-1.0.21
  ronn (>= 0, development)
  rspec (>= 0, development)
  Used by
    Ascii85-1.0.1 (bundler (>= 1.0.0, development))
    acts_as_list-0.1.4 (bundler (~> 1.0.0, development))
    rails-3.1.1 (bundler (~> 1.0))
    thor-0.14.6 (bundler (~> 1.0, development))

Gem bundler-1.1.rc
  ronn (>= 0, development)
  rspec (~> 2.0, development)
  Used by
    Ascii85-1.0.1 (bundler (>= 1.0.0, development))
    rails-3.1.1 (bundler (~> 1.0))
    thor-0.14.6 (bundler (~> 1.0, development))

[swanandp]

Bundler is being used for gem build and push tasks (Bundler::GemHelper.install_tasks) . Its a development dependency. And given the ubiquitousness of Bundler, I am prepared to keep it as a dependency without worrying about its versions.