Convert MapScreen and WaypointCreationScreen to NUI

[BenjaminAmos]

Description

This pull request converts the MapScreen and WaypointCreationScreen UIs to use NUI.

Before

After

Testing

Functional Tests

Map Viewing

• Start a new game or continue an existing one.
• Open the map screen (either using the Map button or by pressing the Tab key).
• Try zooming-in by scrolling the mouse wheel forwards.
• Try zooming-in by clicking the Zoom In button.
• Try zooming-out by scrolling the mouse wheel backwards.
• Try zooming-out by clicking the Zoom Out button.
• Pan the map by holding the left-mouse button on it and dragging the mouse in the desired pan direction.

Waypoints

• The waypoint creation screen should be displayed when the Marker+ button is pressed and a position chosen.
• The three sliders on the waypoint screen should be adjustable from 0 to 255.
• The colour shown at the top of the waypoint screen should correspond to the chosen slider values.
• Clicking Cancel should not place a waypoint.
• Clicking Done should place a waypoint.
• The placed waypoint should contain the colour chosen.
• Clicking the Marker- button and then selecting a waypoint should remove that waypoint

Visual/Scale Testing

• Try to view the screen on different form-factors and screen resolutions.
  Android builds will not see as significant a difference here because they use automatic screen scaling based on the reported display density.
• Elements should not be significantly overlapping.
• Text should ideally not be wrapping mid-word.
• Buttons should be large enough to be confortable to reach on Android.

Notes

• This depends on New NUI widgets (EmptyIfInvisibleContainer, UIBackingBox and UILabelledIcon) #664.
• This supercedes NUI Map screen and NUI WaypointCreation screen #642.
• This should help with Is 2 fingers too much? #563.
• The colour selection has been changed from a scale of 0-1 to 0-255, since I felt that people would be generally more familiar with the 0-255 scale.