Revert "Revert "Create GamePanel.java""

This reverts commit 811813503f9f126f790b60057044740d944faf00.
Revert "Revert "Revert "Create GamePanel.java"""

This reverts commit 2b4127970230db000c4e5e662f531591a4b2adf8.
Merge remote-tracking branch 'origin/master'