Reimplemented compound_statement as a struct

Signed-off-by: K-ballo <k@fusionfenix.com>
Fixed missing debug support for return_statement

Signed-off-by: K-ballo <k@fusionfenix.com>
Changed declaration grammars

Signed-off-by: K-ballo <k@fusionfenix.com>
Track scope name in AST

Signed-off-by: K-ballo <k@fusionfenix.com>