Ensure that a Java SE Runtime is available

[genodeftest]

If running portable there is no way to enforce a system with Java installed. If there is no Java installed we need to
a) load a local Java installation

• what about the license? are we allowed to ship the java runtime?
• can we use Java from the portableapps.com suite?[1]

b) let the user know what he has to do to install java to run RSSOwl

• this makes bad user experience, how do we fix that?

Do we need to make sure to use a 32Bit Java?

Testcase 1 should be used to check if this bug is fixed.

[1] see http://portableapps.com/apps/utilities/java_portable and http://portableapps.com/apps/utilities/java_portable_launcher