Initial TCL Interp support
Add a ScriptInterp::destroy() for deleting interp
Move ScriptInterpTCL implementation to cpp
Add variable linking to TCL interp class
Disallow copying interps.

Not all languages allow easily cloning them, otherwise a reference
counting mechanism would be needed to ensure that the same
interp pointer does not get free()d twice.
Call init() in constructor
Move init()/destroy() protected
Update documenation
Rename cppunit test for ScriptInterpTCL
Add read-only var support
Add linkVar() calls for Int/Long/Double
Simplify prototypes for traces and DRY code a bit
Add boolean var linking
Add (invalid) prototypes for unsigned (int/long) to be implemented later
Add basic command creation
Properly cleanup callback struct when the command is deleted
Support functions which returns int as well
Slightly simplify callback struct creation
Implement argument passing to script command callbacks
Add ScriptInterpTCL::deleteCommand()