Inconsistently named variable slf_win_nxlog_root_dir/slf_nxlog_root_dir causes issues

The readme of this role currently states that there is a slf_nxlog_root_dir variable, specifying the path to NXLog installation. This is inconsistent, as in defaults the variable is called slf_win_nxlog_root_dir/main.yml which is then used in tasks/nxlog.yml. The template that is used in the role, templates/forward-to-central-server.j2, however, uses the slf_nxlog_root_dir.

Also, in the template file templates/forward-to-central-server.j2, there is a newline missing on line 104 which causes the file to parse improperly.

On top of this, the example of the slf_win_log_files variable in the readme.md file is wrong, as the backslashes have to be escaped, (or forward slashes should be used).