an assertion keyword
rename a couple of modules

--HG--
rename : lib/Moops/AssertKeyword.pm => lib/PerlX/Assert.pm
rename : lib/Moops/DefineKeyword.pm => lib/PerlX/Define.pm
an instance of the old Moops::AssertKeyword name
fix code rewriting
assertion tests
improve assertion parsing; document PerlX::Assert
further assertion documentation
bump version; changelog
Added tag 0.012 for changeset a9348349ad0e