Replace overrides.rb with find_template override

[lilith]

Overrides.rb is incomplete and obsolete.

Sinatra offers the find_template method which does the same thing.

See overriding template lookup:

http://www.sinatrarb.com/2011/03/03/sinatra-1.2.0.html

[gma]

Good point, thanks. I'll use that…

[gma]

Addressed in 19ec573c06a9443091919e9142ded96e92fbf76c