Ruby 2.0 support, miscellaneous additions as detailed further below.

* Updating to support Ruby 2.0 by updating dependencies.
* Adding `NXTBrick` examples with no block.
* Adding Bundler binstubs to `.gitignore`.
* Updating `Gemspec` to remove use of `:rubygems` symbol, which is deprecated.
* Started updating `README.md`, partially done.