Added units tests for the Corpus object
Made changes that weren't previously synced from numenta/master
Moved corpus_test under tests/integration
minor argument name change for class function
Use tempfile module and remove resoures redundantly created in setUp()
Minor change in use of tempfile module
Merge pull request #38 from simjega/issue-27

Issue 27: Need tests for Corpus class
Merge branch 'master' of github.com:simjega/nab into issue-28
Cleanup, add more CorpusLabel tests, use tempfile to create files