Validate man page documents options, refs #19.
Add roles support with -R flag, refs #19.

- FC049: Role name does not match containing file name
- FC050: Name includes invalid characters

Currently we only understand roles in Ruby format. Roles must be in a
role path (specified with --role-path or -R) to be checked. Cookbook
paths may now alternatively be specified with --cookbook-path / -B.

This commit introduces breaking changes to the FoodCritic::Linter
interface.
Add environments support with -E flag, refs #19.