saugns v0.4.4. Cli and variable feature expansion. Command-line options: * Add "variable=value" option, to set variables and pass them to scripts. Each variable is passed as `$variable`, and the name must be valid for use as a SAU variable. Each value is restricted to only a number which may have a decimal point. * Make `-e` apply only to scripts after, not to every script. Language changes: * Variable syntax. - Change numerical variable assignment syntax to use a `$` as leading character: `$name=...`, unlike object labels. [Add backward-compatibility deprecated alias, `'name=`.] - Labels (`'name `, `@name`) and variables (`$name`) won't conflict if they have the same name any longer. Now they are separate rather than one dynamically typed variable. - Add `?=` non-overriding numerical assignment; only takes effect for a variable that doesn't hold a number. Has no side effects when skipping evaluation of the expression. - Add `$?name` construct warning when a numerical variable isn't already set to a number. Can be used by itself, or combined with assignment (`$?name=...`) to also do `?=`. If used by itself, the script won't run on failed check. The new cli option and SAU `?=` syntax work together, to allow passing named, numerical arguments to a script. A script makes predefining a value optional by using `?=` to set its default. Using `$?name` requires that `name` be passed, used by itself. Old scripts can be updated to use the newer assignment syntax, without any manual adjustment, using regex search-and-replace: `perl -pi -e "s/'([A-Za-z0-9_]+\\s*)=/\\$\\1=/g;" paths...`