Follow-up to #5280:
1. Make the Rank virtvar actually return a rank object, to be consistent with other Lua API methods
2. Add a RankIndex virtvar to replicate the previous functionality
3. Make RankIndex return the expected 1-based index for Lua
This is a breaking change to the API, but since the original API is less than a month old, the impact should be small.
Many of the recent scripting API enhancements are missing validity functions and validity checks, so this adds them. There are also some documentation fixes and a >= vs. > bugfix.
Load campaigns using the full path provided by the user, not just from the configured mod paths.
Also tweaks initialization based on the campaign having already been cleared in `mission_campaign_clear()`.
1) In commit 770fce8de5, a flag was incorrectly ported from a bit to a flagset, which caused ships not in the tech db to not be removed.
2) Perhaps due to the pilot file upgrade, campaigns which had their tech databases reset would immediately load stale techroom data from the savefile. This change writes the savefile after the reset so that subsequent reloads will load the correct data.
This is a system for storing arbitrary data in the config file and then
easily retrieving it later on. This has full Lua support for exposing
the available options in a custom UI and changing the values of the
options. This ported some of the existing command line options over to
the new system which is opt-in for the moment by using a mod_table flag.
Tyler Blount