Strip Menu now obscures items based on flags_inv

I also made it look pretty
Improved readability of the strip panel with <BR>s
Added checks in Topic()
Greyed out empty slots for easier readability
-Giacom's Feeback
-Belt, ID, and Pockets are no longer blocked by exosuits, as they are still visible
Merge pull request #3826 from Ikarrus/obscuredstrip

Strip Menu now obscures items based on flags_inv