Show error message for content of array

Using Arrays.toString instead for array.toString()
to get better output in the log message
Use PreferenceStore from ServiceReader

Replaced almost all references to the preferences
to go through the preference store.
This should allow for the use of the propertyChangeListener
to detect when a new service is added.
Look up opentox service from preferences with ServiceReader

Replaces hardcoded opentox url

see bug 3040
Removed unused preference page