Prefix 'Instance' with 'Global'

[Instance]s are, by default, local to sections.  This includes the
AssumeFunext sections.  I've gone through and prefixed all of the
[Instance]s inside of AssumeFunext sections with [Global], so they get
picked up by typeclass search.  I haven't (yet) gone through the files
thoroughly to make sure that no other local [Instance]s show up in
sections.

This bit me when trying to do some things in my category theory library.

I may go back and check the remaining instances soon.

Once again, my emacs has removed all the trailing spaces from the relevant files.  I can resubmit this pull request without those line changes if desired.