Http basic example

[georgestephanis]

Provide an additional example, this time via command line curl for testing purposes.

[rmccue]

If we add this, should also note that curl can take --user "user:pass" and will handle it for you; I'd hate people to be using the complex way all the time :)

[kadamwhite]

We've rolled back our coverage of basic-auth in the main rest API handbook docs because we're focusing people on in-browser cookie auth and pointing towards OAuth over basic auth; this usage is covered with the --user "user:pass" context on the basic auth README