Correct bullet in item line

Bullets in a POD list scope need to be consistent.  For sub-lists,
consistently use '+' as a bullet marker.

Addresses
http://www.cpantesters.org/cpan/report/9f946fe0-7d60-11e2-a980-8d8ee9c07e33
Remove redundant ABSTRACT_FROM

ExtUtils::MakeMaker::WriteMakefile ignores ABSTRACT_FROM when ABSTRACT
is present, so remove it from hash arguments.