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
Remove Layer UrlDownloadFieldName property as it is no longer needed for BODAAC.
Removing all references to the wfsLayer property of Layer.
Remove references to WFS Layer picker script.

Also removed 'Data download' section of Layer edit page as all of those fields have now been removed!
Re-adding test which was removed by accident.
Changing `expect(x.indexOf(y)).toBeGraterThan(-1)` to be `expect(x).toContain(y)`. Some usages of the former slipped into our tests along the way and have since been propagating.
Fixed DownloadPanelItemTemplate test as it was incorrect (it did not test what the author had intended).