put config options in =head2, so they are listed in table of contents
tighten up the pod a bit
skip test that relies on 5.014 syntax, as needed

perl5140delta says: "The -C command-line option, when used on the shebang
line, can now be followed by other options [perl #72434]."
Dist-Zilla-Plugin-Test-Compile-2.042

 - fix test failures on older perls introduced in 2.041