initial take-on

The results of running the simple archetype, v1.3.1, along with a couple
of example icons that are used later on in the demo.
tiny adjustments to .gitignore
Removed unit tests by renaming src/test/java directory...

in myapp/dom, to src/test/javaMOVED.

Also:
- updated .gitignore, to also ignore generated .log files.
Renamed domain class, service and fixture

Renamed:
- SimpleObject -> ConferenceSession
- SimpleObjects -> ConferenceSessions
- SimpleObjectsFixture -> ConferenceSessionsFixture

Also:
- added ConferenceSession.png icon
- made associated changes to isis.properties
- updated ConferenceSessionsFixture to delete from correct DB table
- updated ConferenceSessions #getId() and #iconName() (nice-to-have)
- updated @ObjectType for ConferenceSession (nice-to-have)
Renamed ConferenceSession 'name' property to 'sessionTitle'

Also:
- updated ConferenceSession#compareTo
- updated fixture data in ConferenceSessionsFixture
added ConferenceSession date property

also:
- set random example dates in ConferenceSessionsFixture
Added 'type' property to ConferenceSession

Also:
- updated ConferenceSessions#create to populate (since mandatory property)
- updated fixture data
Updated ConferenceSession UI hints

specifically:
- @MemberOrder to order and group properties
- @Hidden (in all tables) for the date property
New Speaker entity and Speakers domain service.

Also:
- updated isis.properties to register the new Speakers domain service
- updated fixture data to create new Speakers
- added icon for Speaker
Added speaker property to ConferenceSession
Adding autoComplete for ConferenceSession's speaker property

Also:
- adding supporting query to Speakers domain service
Added imperative title() method for ConferenceSession

... and removed the declarative @Title annotation

Also:
- added a convenience prototype action to return first session
Added Tag entity and Tags domain service

Also
- added sample fixture data
- updated isis.properties, adding Tags as a domain service.
Added tags collection to ConferenceSession
Added addTag and removeTag actions to ConferenceSession

Also:
- updated fixtures so that 3 random tags are added to every session
Added choices for addTag and removeTag actions in ConferenceSesison
Added ConferenceSession.layout.json

for dynamic layout of UI.  Changes:
- addTag/removeTag are associated with the 'tags' collection
- widths of columns changed.
declarative and imperative business rules on ConferenceSession

specifically:
- declarative validation rule on sessionTitle property
- imperative disable rule on addTag action
Added action on ConferenceSessions, contributed to Tag

Also:
- added corresponding JDO annotations for the query.
Added CssClass hints to addTag/removeTag actions in ConferenceSession