Switch Pod::Weaver from RTHOMPSON to Author::RTHOMPSON
Add a test for just basic functionality.

It just create a dist with one plaintext readme. If this test fails,
then there is a serious problem.
Add test for pruning of root READMEs

This tests the functionality of 82c2e06, which prevents a readme file
generated in the root dir from being gathered into subsequent builds.
Fix typo
Add Changes entry for rootprune.t