Attribution & alt text, minor typo & layout fixes

I made some small adjustments to the text and layout for clarity, but nothing that should affect use of the prior files. However, all three main files (main document, black and white, and text only) have been updated and I've also included a text document with alt text for the symbols and graphics in the document as well as a document with information on the CC Attribution 4.0 license with permission for translation into other languages & contact information. 

Thank you very much!