Revision 189829

Derby-314: improve Eclipse plugin network server process handling.

The fix changes the behaviour to the following:

1) Only one network server can be started per project.

2) Once a network server is started for a project it must be stopped before any
   of it's settings (port, host and derby.system.home) can be changed.

3) If a user tries to change these settings when the network server is running
   they will be notified that they cannot change them, and the text fields
   become uneditable. 

Committed for Susan Cline <home4slc@pacbell.net>