Add ree to .travis.yml

We have some legacy users still on 1.8.7, so we should be running rspec
against that target as well in order to catch any regressions across
ruby versions
Bumped version v1.3.16
Make Listing#respond_to? match #method_missing for Standard Fields

The Listing model uses `method_missing` to allow shortcut access to
standard fields. This change extends that functionality so that
`responds_to?` correctly reports on those shortcut methods.
Merge pull request #79 from mjobrien/listing_sf_respond_to

Make Listing#respond_to? match #method_missing for Standard Fields
RUBYAPI-34 Made ListingCart detect dirty attributes and fixed the
tests
Revert "Add ree to .travis.yml"

There is a series of tests that sporadically fail for strange reasons
using REE. The failures look like JSON conversion errors (hashes instead
of strings or vice versa), which makes little sense to me at the moment,
so I'll revert this out.

This reverts commit f404275a25279df5a19b215649b4ff40af40f045.
RUBYAPI-34 minor docs fix
Merge pull request #80 from GutsyGusty/RUBYAPI-34

Fix issue with listing cart dirty attribute detection
Provide a setter for the logger
Use blocks for logging

Main goal here is keeping the memory usage down when we're calling debug
with huge hashes
Merge pull request #81 from sparkapi/logging_changes

Logging changes
RUBYAPI-34 Needed json library
Merge pull request #82 from GutsyGusty/RUBYAPI-34

RUBYAPI-34 Needed json library