Top level README has outdated instructions for naming files in examples directory

[erichaney]

The "adding examples" section at the bottom of the document currently says that / should be replaced with _ in the file names added to the examples directory.

It should be updated to mention that any of the following characters %*/:<>? should be replaced with an underscore followed by their byte value (or whatever is the best way to phrase this).

See this document by sogaiu for a further discussion and concrete examples.

[sogaiu]

At some point, perhaps it makes sense to add a script or some such to this repository that can be used to generate an appropriate example filename from a symbol name.

May be this would be more convenient (and less error-prone) for users and the instructions in the README would be simpler too?

[sogaiu]

@erichaney Do you think that with the merging of #265 that this issue has been addressed?