Improved donor search functionality (#164)

-- Improved donor search algorithm --
--Improved donor Interface --
--Updated test cases --
fix up of donor repository test (#164)
Updated donor repository in handling strings (#164)
updated comment on a test case (#164)
Fix up of naming issue in donor repository test (#164)
improved Search criteria (#164)
Included dueToDonate field in search criteria (#164)
Updated exactMatch to usePhraseMatch(#164)
Merge pull request #166 from jembi/Improve_Donor_Search_FUnctionality_AND_UI_#164

Improved donor search functionality (#164)