Additional diagnostics for file format checking

Some formats, like shape files, track databases, etc, contain extensive cross-referencing information which can get out of sync. This proposal would add diagnostics to the relevant loading code for checking all such cross-references.

When loading into the main game, these diagnostics would only be abled if selected in the options (i.e. off by default).

When the command-line tool is used to load a file, all these diagnostics would be enabled automatically.

Roadmap: https://trello.com/c/I56ySVFU/287-additional-diagnostics-for-file-format-checking