Lots of Changes

While I was on vacation and was free from interruptions I made a whole bunch of changes to the game:

• Added a message in mail to show that an air mission has failed due to enemy interference.
• Fixed the missing "The server is busy incrementing the turn" dialog.
• Fixed an error in the code for the open company order that kept it from being executed.
• Consolidated the context menu (Right Click) code on all of the company lists. Added "Show My Companies" and "Show Others' Companies" to the context menu. Removed the redundant "Show Only Nationalized Companies" check box from the national government company tab.
• Added the ability to build large capacity storage units.