done with Step 5
Added ShoppingCart and ShoppingCartWithGroceries classes, also added a snowman head
Merge pull request #1 from jdum66/master

| Item | +o?- | Poss | Pts | Summary | Comments  
|------|-------|------|-----|-------------|-----------
| SG   |  o     | 20   |     | SimpleGui1 text/color change |
| SN   |    o   | 40   |     | Snowman has head     |
| C1   |     o  | 20   |     | Two classes draw obj in own package      |
| C2   |    o   | 20   |     | extend GPW, impl Shape |
| C3   |   o    | 50   |     | one class inherits other    |
| C4   |   o   |  40  |     | constructor inits GP obj  | 
| C5   |  o    |  40  |     | obj drawn recognizable (look at the drawing!) | 
| C6   |   -   |  40  |     | good code style (look at the code!) | Missing some javadocs
| GP   |  o    |  30   |     | following instructions |