Fixed git reference to scripts directory.
Added GUI base.

Current elements supported:
 - Xamarin.Forms.Label
 - Xamarin.Forms.StackLayout
 - Enemies.Controls.ImageButton

Usage sample:
new Xamarin.Forms.Label { Text = "Test" }.AsEntity()
Sample GUI component usage.
Created basic Map class.
Merge remote-tracking branch 'remotes/origin/gui'
Merge with GUI.