New USB Link setting capability for all three boards

Details:

--Implemented widgets and underlying software code to enable the user
  to select the USB link number that will be used to attempt to
  connect to the specified device.

--Minor renaming of various items as we move towards a more generic
  implementation for control of CAEN hardware

--Cleaned up and fixed a few minor graphical bugs in the connectino
  frame code.
Implemented GUI interface to select CAEN device type;

Details:

--New combo boxes have been implemented on the connection frame that
  will allow the user to select the device type. These settings will
  be passed (upon connection it) to the BR/DG/HV managers such that
  the correct device-specific interface can be implemented in the
  backend. The implemention is not yet complete.