update meta-spec to v2 and add more author tests
add MANIFEST to the .gitignore list
fake release dates of 1.18_02 and 1.21_7

To be clear: I want the failing date-time format test for Changes to avoid
releases with broken dates. The price of an unknown date being replaced
by an approximated one in a suitable range sounds fair to me.
be more strict in use

* add q[use strict; use warnings FATAL => "all";] to every package
* favor q[use ... ()] over require