install simple-captcha plugin
downloadAuth controller returns captcha link
DownloadChallengePanel to interact with grails app
resetting captcha between requests of same session
resetting of captcha done in DownloadAuthService
tests for DownloadAuthController
gogoduck controller tests with DownloadAuthService
DOWNLOAD_AUTH_TAG as constant
tests for DownloadAuthService
TimedEvictingQueue to keep track of queue items

automatically evicts items older than configured backlog
counting aggregator downloads per ip address
not using DOWNLOAD_AUTH_TAG anymore, users are free to download until they abuse the system
set maxAggregatedDownloadsInTenMinutes in config to 2
better hierarchy for configuration of downloadAuth
cleanups for DownloadAuth

remove unused session variable, div id quoted, better conditional
statements
test correct timed eviction in TimedEvictingQueue
use ms to measure period for downloads
fix log message for download count
label with instructions for captcha
renewing challenge (captcha) by attaching milli parameter