wiki/LICENSE.TXT: documented what this license refers to (the wiki hosted at https://projects.nceas.ucsb.edu/nceas/projects/bien/wiki/)
wiki/LICENSE.TXT: added message about including _license/ when redistributing, as for /LICENSE.TXT
wiki/LICENSE.TXT: changed "the page text of the wiki" to "the wiki's components" since some of the attachments will eventually be marked as open-source
added wiki/LICENSE.TXT,_license/, with license terms that apply specifically to the wiki (which is BSD, not GPL). note that the wiki attachments are NOT open-source, only the page text.