test under ruby 2.1.1
update gem to use engine-cart 0.3
pin to Rails 4.0 and known-working sass dependencies
Update blacklight-marc to use new export features from Blacklight 5.4
bump to 5.4.0
Merge pull request #18 from projectblacklight/blacklight54compat

Update blacklight-marc to use new export features from Blacklight 5.4