Add another triageCorpus (small2) to the test triage db

We wanted another triage corpus to test cases in involving more than one triage corpus.
Revised unit test TriagedDocumentCollectionReaderTest to conform to the data added to the test triage database
Removed unused parameters from TriageScoreCollectionReader.java
Remove ArticleCitation.pmid from sql query in TriageScoreCollectionReader.java

It was not used
Make triageCorpus parameter optional for TriageScoreCollectionReader

If triageCorpus parameter is not specified the collection reader will aggregate the triageScores across all triage corpora
Adds unit test for TriagedDocumentCollectionReader
Set both TriageScore.citation_Id and TriageScore.vpdmfId in TriageScoreCollectionReader

If traigeCorpus parameter is null then TriageScore.vpdmfId = -1 (because it aggregates a citation across all triage corpora)
Rename Unit Test
Make parameter -triageCorpus optional when used with -train in TriageDocumentsClassifier

If triageCorpus is ommited then the model will be trained using all triageCorpora
Merge branch 'master' of github.com:BMKEG/skmTriage