Implement `root_directory` method

After creating the Configuration class, it didn't make sense for
`root_directory` to remain an abstract method, to be overridden by
classes that included ViewHelpers. Now, the `root_directory` method
makes a direct call to `Rubycritic.configuration.root`.
Create `erb_template` method to simplify generators

I don't like the fact that this method is defined at the top of the
class, before the constants. However, this is needed because one of the
constants depends on the method.
Refactor Flog adapter

The refactoring spell used was, once again, [Replace Temp with
Query][1].

[1]: http://ghendry.net/refactor.html#rtq
Rename `smell_location` method to `smell_locations`
Simplify SmellAdapters

Got rid of an enormous amount of temporary variables.