Parse T_ATTR_DECL.
Parse entity_statement_part.
Fix and improve dump_entity().

 * Print "generic (" before dump_generic() callings.
 * Do dump_port() callings only if tree_ports() > 0.
 * Make indent of right parenthesis nicer.
Dump entity_statement_part.
Add assert3.vhd.
Ignore stackdump.
Merge pull request #30 from hiyuh/parse

(imcomplete) support concurrent_assertion_statement in entity_statement_part