cr_citation_count now gives NA when DOI not found instad of 0, closes #36
added cr_citation_count test, #33
fixed weird man file problem in cr_cn
now requiring httr equal to or greater than v0.6 since followlocation doesnt seem to work correctly for cr_cn fxn in lesser httr ver
bumped ver to have .99
bumped date
dont ignore tests anymore
install httr new ver on CI files
started making new crossref api fxns better at failing #37
some changes
cr_fundref tests, #33