Remove extra symbol table implementation, and adopt RTruffleSOM global handling

- also made other classes immutable in universe

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Backported array improvements

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Remove symbol_table.py, should have been part of second to last commit

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Remove invokable.py because it is unused, and most likely outdated

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Fix typo

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Check that Double and Integer always have the proper value type

- and adopt style changes from RTruffleSOM

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Pass class in Object constructor to avoid set afterwards

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Backport minor style adaptations in block.py

Signed-off-by: Stefan Marr <git@stefan-marr.de>