evil hardcoded fix for my project evsukov89/couchbase-lite-ios#4

because in couchdb you can require relative path like require('./foo')
but in order to make it work I need to keep a pointer where I'm in
design doc tree which is a bit crap to do. Since my project only uses
this in functions from lib directory, I can safely replace
require('./foo') with require('lib/foo')
POSTing to list functions