Remove Unicode characters

@nguerrera care to take a look?

I have cleaned up the metadata tests to use \uXXXX escape sequences instead of literal Unicode characters.  In addition, I did a pass over the comments and cleaned them up.  I think in some cases it may be reasonable to have Unicode characters in comments, but all the cases here had seemed better suited by just using actual ASCII characters.

Since I think we are moving our coding guidelines into the wiki soon, I did not update Developers.md with the guidance to use \uXXXX sequences.