Accept identifier index requests

General changes:
* Modify license documentation so it does not appear in GoDoc
* Provide GoDoc doc.go files for all packages
* Write stub help text for each package
* General documentation and minor bug fixes

db/dict.go:
* Broke this file out from db.go to contain dictionary related functions
* Created GetResourceID and GetResourceIndex functions for /dict/{db}/i requests

handlers/dicthandler.go
* Implemented /dict/{db}/i request handling for identifier index requests