Implemented logic for scrollable map view

MapPanel.java:
- Added circle display for maximum range.
- Added grid display on map view.
- Added "center" variable to represent coordinates of current center of map.
- Implemented logic for objects to be displayed based on center & scale of map.

MiscPanel.java: Created panel with text fields to allow user to manually enter data to adjust centering and zooming of the map.

RadarDisplay.java: Added MiscPanel to GUI display.