Added a mod ship screen with a button to access the battle.
Fixed bug in InfoLayer. _border_vertex_list was not deleted on exit.
Added a player.json file for the player fleet. Continued to work on the ship mod page.
Ship mod page has now a list of ships and selecting one displays its caracteristics.
Created a sub-menu which allows to be positioned with it's title on the page.
Shows the different mods in each slot of the ship selected.