Merge branch 'release/0.63' into develop
Spelling corrections
Merge pull request #319 from dsteinbrunner/develop

Spelling corrections
dependency version bumps.
Avoid showing warnings when directly switching between different perl/libs combination.
rebuild
Ensure a clean build environment

We want to begin each new build in a frech directory, so
remove it prior to extracting the tarball. GNU tar's
--recursive-unlink option will "empty hierarchies prior
to extracting directory".

Fixes gh-295.
Fix spurious test failures
Fix clean and have it remove tarballs, too
add a proper doc section for clean
add a switch to turn off man pages
Use www.cpan.org as mirror

http://www.cpan.org is a global load balance DNS record that directs to
close tier-1 (fast updating) CPAN mirror servers.

http://search.cpan.org/CPAN redirects there anyway, so let's avoid the
extra re-direct
Use CPAN src index directly

For finding perl tarballs or listing available Perl's, we can
look directly at http://www.cpan.org/src/5.0/ rather than
rely on CPAN::Perl::Releases or scraping search.cpan.org.

This commit also adds an "--all" flag for "available" to list every perl
tarball available.
Merge pull request #321 from doherty/clean-builds

Clean builds
Merge pull request #329 from dagolden/topic/no-manpages-switch

add a switch to turn off man pages
Merge pull request #326 from dagolden/topic/clean-tarballs-also

Fix clean and have it remove tarballs, too
Merge pull request #330 from dagolden/topic/use-official-cpan-mirror

Use www.cpan.org as mirror
Merge pull request #331 from dagolden/topic/use-cpan-src-index-directly

Use CPAN src index directly
Add switch to build perl with threads
add support for some predefined compilation flavors: thread, multi, 64int, 64all, ld and debug; rename threads to thread for consistency with how this flavor is usually named while keeping support for the old flag