* added getAvailableVersion(), moved _httpClientTimeout and _followRedirects to protected, added enum HTTPUpdateError
* auto numbering of HTTPUpdateError enum
* added getAvailableVersion(), debug output current current Sketch MD5
* Revert "added getAvailableVersion(), debug output current current Sketch MD5"
This reverts commit 60d2c7762e.
* Revert "auto numbering of HTTPUpdateError enum"
This reverts commit 61785b27da.
* Revert "added getAvailableVersion(), moved _httpClientTimeout and _followRedirects to protected, added enum HTTPUpdateError"
This reverts commit cec84ed17a.
* add redirect function
* enhanced redirect() by cache control and client stop
* updated redirect() comment
* replaced redirect() API calls in examples
* server.client().stop() not needed, redirect() does this
