MergeTopics controller, split out of SplitTopics.
(this PR is a reiteration of the original experiment on merge topics,
that wasn't pulled in)

Signed-off-by: Norv <a.w.norv@gmail.com>
Adapt controller functions names to naming patterns.
(keep split* and merge* to avoid conflicts, as long as they're functions
not methods)

Signed-off-by: Norv <a.w.norv@gmail.com>
Move merge subtemplates to MergeTopics template file.

Signed-off-by: Norv <a.w.norv@gmail.com>
Small doc update.

Signed-off-by: Norv <a.w.norv@gmail.com>
Add messageInfo() to subs. This looks like a duplicate though.

Signed-off-by: Norv <a.w.norv@gmail.com>
Refactor messages selection from a topic.

Signed-off-by: Norv <a.w.norv@gmail.com>
Merge pull request #111 from norv/mergetopics

Merge topics