An OS-general means of:
* generating a unique temp file name
* removing a given file (for cleaning up temp file)

Fix Windows implementation of airTime()

fix airSinglePrintf to not put a space before double-type special values
("%4s" hack has to go)

complete fprintf/sprintf/printf stand-in: use trio?
complete fscanf/sscanf stand-in

Decide if air will have a general-purpose thread-safe progress indication
scheme, or if this will be each library's responsibility
