Refinement to default sort for public ui

For the public interface only apply a default sort if there is no
query (including advanced queries) and no sort specified. This
addresses the problem of meaningless "unsorted" browse views,
but preserves relevancy as the default sort for queries.
Use the new build env on Travis

faster vm boot times
more cpus and ram
better network

docs coming soon
Fix EAD exporter

Replace / or space characters in unitid with _ for EAD filename
in zip.

Also move request handling into module that is included by
ead_export and can be included in other scripts as needed.
Remove test setup that is no longer used anywhere.

This was causing transient failures in the unit tests, because the
preference setting was hanging around after the unit tests had finished.
Since it's not used anyway, we might as well zap it.
Modify subject unit test to allow it to pass when run in isolation
Fix bug in directional relationships caused by the Array() method.

We were assuming that Array({:some => :thing}) would give:

  [{:some => :thing}]

but it actually gives

  [[:some, :thing]]

Fixed by porting the ActiveSupport "wrap" method into ASUtils and using
that instead.
Modify EAD export test to make it pass in isolation
test for converter mappings that target non-existent schema properties
raise a ConverterMappingError when a definition's target isn't in the schema
change the way files are unlinked after a failure so we don't get fooled by the validations
only unlink if the files are there
a better way to strip note mappings
Use the new build env on Travis

more ram, dedicated cpus, better boot times
Update README.md
adding date to be required for resource and fix for non-editable enums
remove mixed content in MARC export
adding finding_aid_title to public view to replace title
tweak to link to contrib pdf
Merge branch 'master' of https://github.com/archivesspace/archivesspace
first pass at log watcher