Update 1.1

A couple of issues with the game have come to my attention so I fixed them.

-Fixed AI going too fast on smaller resolutions
-Fixed (improved handling at least) portal non-responsiveness bug
-Fixed keeping resources after death bug

-Improved tutorial by allowing keyboard navigation for back (back) and forward (enter/return)
-Improved credits by crediting music title and author in more prominent location

Also, I automated away the 'empty ship inventory' button, because the user would always have to press it. (There was no reason not to press the button, therefore the choice is pointless and shouldn't have been there).