Change internal representation of symbol visibility
Store ELF symbol visibility in the database

Add visibility column to symboldb.elf_definition
and symboldb.elf_reference.
Store ELF symbol type in database

Add symbol_type column to the symboldb.elf_definition and
symboldb.elf_reference tables.
Store ELF binding type in database

This adds the "binding" column to the tables symboldb.elf_definition
and symboldb.elf_reference.