Alt text

proposed resolutions for some alt text bugs on CR branch:

- Bug 20401 https://www.w3.org/Bugs/Public/show_bug.cgi?id=20401 - non
   conforming use of title attribute in example code
- Bug 20402 https://www.w3.org/Bugs/Public/show_bug.cgi?id=20402 - use
   of title attribute in example is incorrect
- Bug 20403 https://www.w3.org/Bugs/Public/show_bug.cgi?id=20403 - spec
   states plural conditions when only 1 condition is conforming
- Bug 20405 <https://www.w3.org/Bugs/Public/show_bug.cgi?id=20405> - plural
   'conditions' used when only one condition exists