Added AodaacDownloadHandler
Build AODAAC URL in AodaacDownloadHandler
Remove commented-out code. Features can be added when AODAAC support for HDF and list of URLs is added/fixed.
Tidy way query string is built - less repetition.
Added download handlers for BODAAC and GoGoDuck
Moved menu item functionality from WmsInjector, NcWmsInjector to *Handler classes.

Step 2 no longer needs to know which aggregator will be used.

Removed Aggregator class hierarchy (moved to *Handler) classes
Added URL generation for GogoduckHandler onclick function
BODAAC changes
BODAAC changes
DownloadHandler common superclass
DownloadHandler common superclass
Rename variable
Don't use HandlerParams where possible
Getting BODAAC handler ready, but still using values from DB (not metadata record).
Remove some debugging
BODAAC construct URLs from database info
Extra char
Some refactoring to move common things up to DownloadHandler
Removing tests for removed functionality
Removing unnecessary comments