Removed non-ascii, '&' in file is troublesome\!

Here is a request to change the name of a file to remove the troublesome '&'
And a fix for the non-ascii characters that plagued the bring up of
`jekyll serve` on my MacBook Pro yesterday in class.

George Wood

Please change the name of
`slides/_posts/advanced/remote/0001-01-01-Custom-Fetch-&-Push.md`
to 
`slides/_posts/advanced/remote/0001-01-01-Custom-Fetch-and-Push.md`

As the `&` causes the bash shell to stop parsing at that point and push the partial command with the partial filename into the background to mess things up.

George