Implementation for filtering by minAge/maxAge

Should test/compare against web interface
Fix minAge/maxAge queries to match php
Remove leftover findByFilter method
Add async dependency
Simple implementation of async fetch
Use async.map

Saves 24 lines of code over async.each, everything fits nicely into
callback(err,result)
Merge pull request #1 from dleehr/filter-minmax

Implement minAge / maxAge filter