A little bit more from the parser

Ok, I think that the parser is working for all the changes in the 2.5 grammar

Adding the unified try..except..finally statement was only a change in the grammar, and it produces the same AST as if it was a try..finally with a try..except, so no semantic changes should be needed.

The new "with x: ..." statement was also added, but I still have not checked which semantic changes are needed. It will also need a new keyword in the syntax highlighting.

So, the parser is now almost complete... almost because now we have to mark those new constructs as invalid if the grammar is in 2.5 but you're using code in 2.4. Still, that should not be difficult to do.