Hash each item before doing the comparison.

Credits go to @gaffneyc:
https://github.com/martini-contrib/auth/commit/3dc6cad753d9398fc1cad43c98136e840c9e91e3#diff-3f1ad41879763caf285707f64678af17
Added BasicAuthFunc
update readme with up-to-date repo
added *http.Request to BasicAuthFunc callback to let the user decide how to pass on the username
Merge pull request #4 from cryptix/usedOldContribRepo

Updated auth middleware with BasicAuthFunc