(maint) spec: allow expectations of resources from compiled manifests

Add logic to the PuppetSpec::Compiler.apply_compiled_manifest method so that
a spec test can supply a block that processes the single resources
that comprise that catalog that was compiled before it is run in a transaction.

As a proof of concept and general helper, add a apply_with_error_checks method,
that adds an expectation to never send an :err signal to each resource. This
makes spectest debugging much easier, because without expectations,
the transaction will just finish and the only reported error will be that the
end result is not as expected. When the expectation is added to each resource,
rspec will display all resource error messages as failed expectations.
(PUP-2822) Improve description of disable_warnings setting
(MAINT) Small openbsd package spec tweaks

- use .tgz as the package extension
- complete 'provider features' and sort lines
(maint) use compiler in crontab integration spec
Merge pull request #2754 from ffrank/maint/compiler-spec-catch-resource-errors

(maint) spec: allow expectations of resources from compiled manifests
Merge pull request #2798 from jasperla/openbsd_pkgspec

(MAINT) Small openbsd package spec tweaks
Merge pull request #2793 from nfagerlund/docs_disable_warnings

(PUP-2822) Improve description of disable_warnings setting
Merge branch 'master' of https://github.com/puppetlabs/puppet