*8854* Added tests for getRemoteAddr trust_x_forwarded_for config setting

Added unit tests for http://pkp.sfu.ca/bugzilla/show_bug.cgi?id=8854
Sorry to be pedantic about this, but please flag it in a comment as being a necessary reference. As we go around removing reference use (we had to use references almost everywhere for PHP4) it's all to easy to nuke a needed one like this.