This requires splitting the `used` field into digital and analog components. The digital field stores the last-used timestamp, whereas the analog field stores the last value.
Allow the variables controlling ship shudder to be independently set using scripting. Also add new flags to apply the shudder without decay and apply the shudder regardless of camera.
Also change the shudder timestamp to the new style.
Previously, the game used a dead-reckoning system for measuring time, where several time counters were incremented as long as time was running. This unfortunately has no way to synchronize time in the long term, and therefore in-game time will tend to run faster or slower than real time by a few percent, depending on various factors.
This PR redesigns the timestamp system to use the SDL time counter which will always keep it in sync with real time. However this necessarily involves a bit of clever handling when the game is paused and unpaused. It also revealed several minor bugs in several places in the code where timestamps were handled.
This PR is currently in draft status until the design can be updated to handle time compression. In all other respects it should be working.
The largest new feature is that it is now possible to include other
files into the RML by using the "include" tag. This is useful for making
markup files more modular.
Also added some more options for existing things (e.g. built-in detail
options).
Currently there are multiple locations in the code where the version is
constructed by printing the individual numbers together. This is mostly
sufficient but it hides information such as the commit hash or the build
name (e.g. RC1). These changes unify that behavior by always using the
version string generated by CMake.
Goober5000