Implemented DELETE and DISPLAY for ITEM table
Implemented INSERT for the LEADSINGER table
Implemented DELETE for LEADSINGER
Imlemented DISPLAY for LEADSINGER
Fixed conflict in itemTest.java
Implemnted INSERT and added a test file for HasSong
Implemented DELETE for HASSONG
Implemented DISPLAY for HasSong
Added checks for Item's type and category
Merge pull request #3 from ellina-s/arjan

Arjan
Resolved conflicts with master
Merge pull request #4 from ellina-s/ellina

Ellina
Merge pull request #5 from ellina-s/arjan

Populated Tables for Testing