This is a follow-up to #2687. The final implementation of evaluateNumericSEXP different from the testing implementation in a small but crucial way that prevented it from actually working. Since it used `eval_num`, it didn't evaluate the specified SEXP node but rather the CAR (first element) of the node list. This fixes that by putting the node in a temporary SEXP list so that `eval_num` will look in the right place.
This refactors the tolower/toupper code to use standards-conformant logic, and also adds some helpful utility functions. Regular tolower/toupper must be supplied a value that can be represented as `unsigned char`, but the std:: functions are a bit more robust.
Implements send-message-chain as described in issue #3185. Also fixes the default argument for message priority, and mirrors the default argument fix to qtFRED.
One small detail that was overlooked in PR #3021... KeldorKatarn's old code used `strtod` while the new code used `stuff_float`. This wouldn't be a problem except that a couple MVP models use annoyingly formatted floats like 8.9e-08. So I decided to convert `stuff_float` to use `strtof` and do some more upgrades while I was at it.
For compatibility purposes some mods want alt names to truncate at the hash symbol. But we can't actually do that at mission load,
since we have to save them again in FRED. So this commit processes the names just before the mission starts.
To further complicate things, some mods actually want the hash to be displayed. So this commit introduces the double-hash as an escape sequence for a single hash.
* Can't simply use the previous fade_out color as the default, because of an edge-case with legacy usage. The refactor would disallow setting the fadout to black.
This is a follow-up to PR #2942. Given that the short-circuiting is now explicitly skipped for node trees containing the special argument, it should no longer be necessary to flush the conditional branch of the sexp tree. (The .cache field is already skipped for special-arg nodes.)
The sexp tree is still explicitly flushed for `every-time` and `every-time-argument`.
It takes a number as a maximum number of arguments that can be evaluated in a single call, but otherwise behaves very similarly to `any-of`; alternatively, if the number is 1, it's like an `in-sequence` that also skips arguments that don't satisfy the condition instead of just invalid ones.
If a message string contained a word that was too long, on its own, for the available screen real estate, the function wouldn't split the string at all. The new behavior is to split the string even if the split location is suboptimal, since it's better to have as much of the message visible as possible.
Quoting from the code:
```
// only update the line break if:
// a) we don't have a line break yet;
// b) we're still within the required real estate
// (basically we want the latest line break that doesn't go off the edge of the screen,
// but if the *first* line break is off the end of the screen, we want that)
```
* Fix underline length calculation in message scrollback
* Use SCP_string for message source (which allows ships with long display names to work without crashing) and message text
* Upgrade assorted functions to work with SCP_string
JohnAFernandez