Merge pull request #1 from aguibert/master

initial changes
Merge pull request #2 from aguibert/master

design changes
Merge pull request #3 from aguibert/master

hw2
Merge pull request #4 from aguibert/master

Andy's update'd hw 2 and 3
Merge pull request #5 from aguibert/master

Visitor pattern powerpoint
Merge pull request #6 from aguibert/master

Relational database code + example
small commit before package changes
Revert "small commit before package changes"

This reverts commit cbe4457b5ac558dcc1ccbfbc0d836601f6332efb.
Merge pull request #7 from aguibert/master

Rename "Package" to "SystemPackage"
1st Iteration Warehouse and WarehouseManager

+ modifications to databaseImpl and creation of SystemPackageImpl
1st iteration fixes
Merge pull request #1 from jdmielke/master

1st Iteration Warehouse and WarehouseManager
Iteration 1 Invoice code
Merge pull request #3 from aguibert/master

Iteration 1