handle missing publication type
Merge pull request #35 from articlemetrics/dev-crossrefMissingPublicationType

Handle missing publication type in crossref data
fixed error in searchplos and changes to iterate by 1000 instead of 500
added travis-ci yaml and makefile files, updated readme
minor change to readme
small edit to travis-yaml
small yaml change
travis yaml file name was spelled incorrectly
Merge remote-tracking branch 'upstream/master'