'zic -v' now warns about all '.'s in output file names.

* zic.c (componentcheck, namecheck): Warn about all '.'s in
the file name, not merely about "." and ".." file name components.
* zic.8 (DESCRIPTION), NEWS: Document this.
* Theory, NEWS: Also document EST5EDT etc. as exceptions.

Use the term "legacy names" for exceptions.