Port on docs 2.10 branch changes from r1537165


URL: http://svn.apache.org/r1537165
Log:
Changing the header of website (new arrangement)
Adding twitter link into menu
Putting the ApacheCon link in the bottom of menu
Ref. The thread started from this message:
http://mail-archives.apache.org/mod_mbox/jmeter-dev/201310.mbox/%3CCAOGo0VZemLq4LkWSK8WVU14-vJGxOH3AHHbA1QQqN0DvUX6GSg%40mail.gmail.com%3E 




git-svn-id: https://svn.apache.org/repos/asf/jmeter/branches/docs-2.10@1537169 13f79535-47bb-0310-9956-ffa450edef68