Preliminary backend support for tactical destroyer modes.

* Modifies fits table to add "mode" column, which contains typeID of mode for fit
* Introduces Mode type, similar to Ship and Module type
* Includes effects for Amarr Tactical Destroyer Propulsion Mode

Still a lot to do: GUI switching, constraints on which ships get modes, etc

config.py

@@ -21,7 +21,7 @@ evemonMinVersion = "4081"
 
 # Database version (int ONLY)
 # Increment every time we need to flag for user database upgrade/modification
-dbversion = 2
+dbversion = 3
 
 pyfaPath = None
 savePath = None