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 command) if it's 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]|