Merge branch 'release-1.0' into development
Restricts instantiation of data types to model

Airports and countries onyl get instantiated by the class 'Model'.
Every other class works with these objects.
Introduces menu bar to application

The footer gets removes and substituted with a menu bar. This is
a preparation for future commits, especially for some features to
be implemented.
Adds icon for application

The application gets a small icon for a better user experience.
Provides option to change enterprises, closes gh-16

In previous versions the user could only choose the enterprise
when starting the application. To change it he had to restart
the program. This has been adjusted by introducing a new menu
item which allows to switch the enterprise on-the-fly.
Adds icons to menu

This commit contains a set of icons for the menu. The icons are
from an excellent icon set by Oliver Twardowski named "addictive
flavour".
Fixes several bugs leading to Exceptions

Several bugs exist that trigger Exceptions when working with the
table. First a NullPointerException gets triggered when the editing
of a cell gets canceled without a value in it. Second another
NullPointerException gets triggered when DELETE gets hit and no
row is being edited. And the third exception is a
IndexOutOfBoundsException that gets thrown whenever DELETE is hit
and no row is selected. These bugs get fixed with this commit.
Resizes menu icons

The menu icon are a bit too big, so this commit provides menu icons
with a size of 16x16 instead of 24x24.
Implements update, prepares for gh-17

With this commit the UpdateManager gets added, a class responsible
for checking if the database is up-to-date, and to support it
several changes have been made to the application.
Implement test for UpdateManager

To verify the correct behavior of the update a test has been written
that performs an update from version 1 to 2.
Implements airports per enterprise, closes gh-17

This introduces the feature that airports are selected per
enterprise to reduce the size of available airports when
creating routes. Internally this is done by associating
airports and enterprises using a n:m relation.
Fixes bug in airport initialization

An error existed in a SQL statement that was processed during the
initialization of the model. More specificially a parameter in a
PreparedStatement didn't get used.
Merge branch 'enterprise_has_airport' into development

The feature is implemented and allows to reduce the amount of airports
listed when creating routes to those airports that where actually created
by this enterprise. If different enterprises are in use that exists and
operate in totally different regions only the airports in the respective
region will get displayed in the future.
Fixes bug with enterprise-to-airport association

In certain conditions the association was not added correctly or
twice, which led to NullPointerExceptions. This has been fixed.
Updates database to version 2

Despite all the activity with the new features noboby noticed that
the database is still on version 1.
Fixes bug preventing enterprise creation

Due to cyclic requirements when creating enterprises and airports
a NullPointerException was triggered, which gets fixed with this
commit.
Introduces option to delete enterprise

To delete an enterprise all its routes and the enterprise-airport
associations get removed before the enterprise itself gets removed
from the database.
Bumped version to 1.1
Release 1.1

The main feature of this release is an improved user interface, where
the bottom panel has been substituted with a menu bar to allow greater
flexibility and more options. Additionally small modifications where
made to the way multiple enterprises are handled and the issues they
create.