Added DeclareFile AST node
Add FileToplevel component, now generated by DeclareFile AST node

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extra : amend_source : a06ff8ecfaa1c3b91527cd4792fb34b88026e49c
Added parent accessor to instance and component
Added id readers for the start of id introspection

--HG--
extra : amend_source : da3fada3b6e4212ab07ffe3fbe9fe13398faac72
Added id_scope reader to Component and Instance
Make parent of a new Component an argument of new rather than an after-the-fact accessor
Make id resolution script-local in AST by storing in constant table of id_scope

--HG--
extra : amend_source : 47d595d936a3bdb1b1a4f8f6795995d373ebb8f8
Added get_by_id to Component and Instance

--HG--
extra : amend_source : 006aebfaa8b127f56f65af9770ecfb22f469a24a
Implement introspection of filename
Fix category inheritance