Fix hasDateProperty()

To our shame we didn't test this when adding it. The date_properties array is an array of properties, not an indexed array of values. So use the correct in_array().
Make the SwatDetailsViewField's header title come from a method and update the vertical field to use it.

This fixes two issues in the SwatDetailsViewVerticalField header:
 * It now respects the show_colon property.
 * It now shows a &nbsp; when no title is set, just like SwatDetailsViewField
Add docs.
Merge pull request #23 from isaacgrant/show-colon

Make the SwatDetailsViewField's header title come from a method
Merge pull request #22 from isaacgrant/fix-has-date-property

Fix hasDateProperty()
Kill no longer necessary PACKAGE_ID

:skull: death to old cruft.
As no active package uses the package_id anymore, remove it completely.

While here also remove dead addTangoAttribution() method nothing calls anymore.

This should require a minor version bump as it breaks the api.
Bump the package minor version as dropping the PACKAGE_ID constant and use breaks the public API.
Update how we set the default type on SwatMessage.

Instead of having the default type in the parameters, set the default type if type is left unset. This allows code that calls SwatMessage to pass null into the creator and get whatever SwatMessage uses for a default.
Merge pull request #24 from isaacgrant/swat-message-default-type

Update how we set the default type on SwatMessage.
Merge pull request #21 from isaacgrant/kill-package-id

Kill no longer necessary PACKAGE_ID