db_schemas: align datatypes in SQL statements
db_schemas: update checksums
ZipFile: close #116; return array of zip members instead of ref

- When `get_zip_members()` is called, return an array of files, the
  members of the zip, instead a reference to that array
- Updated POD to make the return value more explicit
db_tool: add more verbose error/help output
wadindex: tighted up regex that finds WADs in ZIPs

- Info log the contents of zipfiles that don't have a WAD file, in
  order to make it a bit easier to figure out if something's wrong
  with the WAD detection regex
ZipFile: close #119; handle errors from Archive::Zip

- Rearranged methods in the object so they're in alphabetical order
  from top to bottom of the file