[nemo-qml-plugin-calendar] Support converting event to vCalendar

This commit adds an invokable function to the NemoCalendarEvent type
which returns the vCalendar representation of the event as a string.
This is useful for sharing the event.
Merge pull request #10 from chriadam/vcalendar

[nemo-qml-plugin-calendar] Support converting event to vCalendar
[qmldir] Add Module Identifier Directive
Merge pull request #11 from thp/module-identifier-directive

[qmldir] Add Module Identifier Directive
[nemo-qml-plugin-calendar] Coalesce AgendaModel queries
Merge pull request #12 from aaronkennedy/master

[nemo-qml-plugin-calendar] Coalesce AgendaModel queries
[nemo-qml-plugin-calendar] Expose whether notebook is the default one
Merge pull request #13 from pvuorela/master

[nemo-qml-plugin-calendar] Expose whether notebook is the default one
[nemo-qml-plugin-calendar] Avoid warnings on unused variables
[nemo-qml-plugin-calendar] AgendaModel showing events inclusive between start and end.
Merge pull request #14 from pvuorela/master

AgendaModel to show events inclusive between start and end date
[nemo-qml-plugin-calendar] Use correct offset for calendar reminders.

The intention is that the reminders for calendar events are
triggered before or at the start time of the event. This is done
by setting a negative start offset for the reminder.
[nemo-qml-plugin-calendar] emit change signal when changing to no reminder.
Merge pull request #15 from pgerdt/fix-reminder-offset

[nemo-qml-plugin-calendar] Use correct offset for calendar reminders.
Merge pull request #16 from pvuorela/master

[nemo-qml-plugin-calendar] emit change signal when changing to no reminder
[nemo-qml-plugin-calendar] Avoid endless loop when editing event end time.

On handling changes, removing old events required them being
considered less than new event. Inserting new events to an index
required them being less than old event.

When editing ending time of an existing event, neither of the
conditions applied. Thus the loop didn't proceed.
Clean up whitespace
Merge pull request #17 from pvuorela/master

Avoid endless loop when editing end time for an event
[nemo-qml-plugin-calendar] Avoid all day events from showing up on next day
Merge pull request #18 from pvuorela/master

[nemo-qml-plugin-calendar] Avoid all day events from showing up on next day