Feature/fix doc links

@brutski Please review and merge.

This PR fixes links in the README that must use YARD {file: ... } format because relative links need to inject 'file' in the path per YARD generation of files in 'doc' folder.
https://github.com/mdsol/crichton/pull/204/files#diff-4d2b1dfe688ef6ef592d488550ac393eL137 oddly rendered.