rearrange Imager's test files. RT #84596

Imager::Probe::_gcc_lib_paths now forces C locale.
A sufficiently recent gcc prints localized keys for the search paths, which avoids that localization. RT #84963

fix a pod error detected by Pod::Simple 3.27 and later and skip pod tests unless AUTOMATED_TESTING or IMAGER_AUTHOR_TESTING is set and true. RT #85262
reported by Andreas König

add a test for unclosed POD in C source, and fix the errors it found. RT #74875

fix some spelling errors detected by the newer aspell in Debian Wheezy.

remove a trailing ' from lib/Imager/Font/Test.pm's POD thanks to gregor herrmann <gregoa@debian.org> RT #85413