src/test/groovy: use single quotes for creating strings.

@see http://codenarc.sourceforge.net/codenarc-rules-unnecessary.html#UnnecessaryGString

Reported by CodeNarc.

No functional changes.
IDEAS.txt: added
-1: updated series/info prototype.
-1: added prototype for collection/info
ADD_SERIES_TO_COLLECTION -> UPDATE_COLLECTION
-1: implemented basic controllers.
+2 ideas
added servies with fake implementation
updated IDEAS
Added entities.
-1: create collections for existing users
UserServiceImpl: rename a few members.

No functional changes.
finally implemented methods for add/remove/contains series in collection
-1: implemented collection info page
-1: show flash messages
updated NEWS