[#765] [#924] ydbinstall returns error if UTF-8 mode install failed; also terminates after processing command line if not run as root, unless --dry-run is specified

ydbinstall.sh previously reported success for installing YottaDB in UTF-8 mode, even though it actually failed. Now, the installer will correctly report its success. [#765 (closed)]

The check in ydbinstall as to whether it is running as root is made after processing the command line. Unless --dry-run is specified, it terminates with an error at that point, rather than after further processing and downloading. [#924 (closed)]