new operators for expressions (strings, types/evaluators, maybe var-arg like)

[ped7g]

new operators for expressions: strings, types/evaluators, maybe var-arg like

• [ ] do it.
• [ ] abs
• [ ] make sure it's possible for example to handle the _VERSION reasonably and not with warnings like now with long versions strings.
• [ ] make sure it's possible to do various string buildings from arguments in macros, also splitting, etc.

Probably mildly depends on labels refactoring and operators precedence (not that it really needs those, but would conflict with them if done in parallel).