Updated documentation to show more config options

accountUpdatePath wasn't mentioned in the documentation, but is quite important for anyone connecting to a non Devise api. While it's easy enough to find in the source I've added it and accountDeletePath to the doc for completeness.
There are a two more config options which aren't mentioned in the doc (namely validateOnPageLoad and forceHardRedirect), but I haven't added them here in case there is a reason they're left out of the doc.