Fix edoc generation
Add Travis CI
Return the servers when asked to do so

Return the elarm_server children - not an empty list (as it does now),
not a list containing the elarm_registry (as a badly written patch
could do).
Add unit tests re which_servers
Merge pull request #25 from lastres/fix-edoc

Fix edoc generation
Merge pull request #26 from lastres/travis-ci

Add Travis CI
Merge pull request #27 from lucafavatella/fix-which_servers

Fix internal elarm_sup:which_servers/0 and test which_servers
Fix typo
Add additional supervision level on top of elarm servers...

... in order to move the 'which_servers' function down from elarm_sup,
as elarm_registry:init cannot invoke elarm_sup:which_servers - or it
gets stuck.

No externally-visible functional changes yet (this change prepares the
ground for a following change).
Fetch current list of servers when elarm_registry restarts after crash

The change in elarm_man_sup_sup is needed in order to prevent that
elarm_registry, while starting, waits indefinitely for
elarm_man_sup_sup not started yet (or being restarted).

Fixes https://github.com/jonasrichard/elarm/commit/c69b05840ad9c0dabd9f83b554fdc690cc96a710#commitcomment-6459372

Implements https://github.com/jonasrichard/elarm/commit/c69b05840ad9c0dabd9f83b554fdc690cc96a710#commitcomment-6489435
(implements change to elarm_registry:init *and* the supervision tree
in order to avoid cycle dependency on elarm_sup)
Merge pull request #28 from lucafavatella/fix-elarm_registry-after-restart-does-not-monitor-servers

Fix elarm_registry that after restart does not monitor servers
Do not ignore the Opts argument in elarm:start_server/1
Clarify internal function name
Avoid the need to register elarm_summary_sup...

... by teaching its ancestors how to retrieve its pid in the
supervision tree.

This removes the need for gproc, at the price of a bit more complex
code. Fixes #19.
Do not keep unnecessary state across unit tests

Changes:
* Use Where = 'spawn' (default) rather than 'local' (discouraged);
* Use foreach rather than setup.

This change allows each test to assume that the mailbox is clean.
Teach elarm_summary to always use the same ref for notifications...

... also for the first summary.
Merge pull request #29 from lucafavatella/fix-ref-of-first-alarm_summary-notification

Fix ref used in first alarm_summary notification, and improve test
Merge pull request #30 from lucafavatella/remove-gproc-dep

Remove gproc dependency
Do not call lager as it is not guaranteed to be present

I am not sure what approach is the best for a debug log entry, so only
commenting the lines at the moment.

Fixes the following warning:
```
Unknown functions:
  ...
  lager:debug/2
```
Fix `elarm:get_alarm_by_id`...

and .. fix type spec of `elarm:get_alarms`.

This was not caught by Dialyzer.

The `{ok, ...}` bit in the return type of `get_alarms` was already
used in the tests. See
https://github.com/esl/elarm/blob/3350c195c23e371dbe5be6e7ed858e9bf016df63/test/elarm_subscr.erl#L65