Style update (drops Ruby 1.8)

* Changes symbol hash syntax to Ruby 1.9 style
`:hello => 'world'` becomes `hello: 'world'`

* Removes curly braces from hash arguments to methods
`obj.method({:key => value})` becomes `obj.method(key: value)`

* Adds spaces around curly braces in blocks
`{|x| x.method}` becomes `{ |x| x.method }`

* Reduces all lines to less than 80 characters
* Removes 1.8 Ruby varieties from travis.yml