Wrap data prep tests in a subtest for cleaner TAP

The tests only happen once, but it can be confusing to see them when varying
which test are run.  Since it's all related, stick it under one group.
Then it only counts as 1 test in the end.
Edit README.md
Update README.md
Correct doc on value of release.status for dists with only developer releases

The claim that "latest" is used for distributions with only developer
releases may have been true at one point, but since 6997f94, "reworked
latest script", the Latest script has pegged maturity to "release" only.

This makes sense as the "latest" status is supposed to be a reflection
of 02packages from PAUSE, and PAUSE never indexes developer releases.
Configure travis to build 5.20
Allow failures on 5.20 for now; 5.18 seems ok
Only add indexed modules to a file document.

In the case of Package::Stash 0.36 the first-in logic was preferring
t/lib/Package/Stash.pm over lib/Package/Stash.pm

Fixes #331.
Merge pull request #329 from CPAN-API/talina/documentation

Talina/documentation
Update README.md

Updates README to use Carton where appropriate.
if var/tmp does not exist create it for the tests
make Perl::Critic happy
Merge pull request #335 from CPAN-API/leo/puppet3

if var/tmp does not exist create it for the tests
Test that release does not contain unexpected modules

* If testing any modules, require that all are specified.
* Don't skip modules that aren't specified, again require all to be specified.
* Make the test its own subtest.
Make Test::Routine test names more descriptive

Use spaces to help avoid clashing with other attributes and methods.
Make failed module tests more descriptive/helpful
Test that packages get assigned to the right files

when there are multiple matches for path components.
Match the shortest path for 'provides' modules

Fixes the previous tests.
Use -- so that all args pass to prove

For example, don't let carton consume `--help`.
Create .editorconfig for consistent indent style

[ci skip]
Remove carton, carton-exec and daemon-control.pl

These are now all done via puppet on the
development and production machines.

Replaced by:

~/bin/metacpan-api-carton
~/bin/metacpan-api-carton-exec
/etc/init.d/starman_metacpan-api