Slim Script table: fix symbol in parameter display

- Implement construction of script table with "script:" keyword in the same column of the class name as anticipated in SlimTableFactory

You can write:

|script|MyClass|

or 

|script:MyClass|

like other tables

- Display parameters values used in an Actor constructor (created by script and start commands) if parameter is a symbol

If X is a variable set to 100, when test executed, we have before:

|script|MyClass|$X|

and now:

|script|MyClass|$X->[100]|