Update architecture manual page.

  - Added more cross-references.
  - Fixed some spacing issues.


git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1578180 13f79535-47bb-0310-9956-ffa450edef68
Add more info to logging separation documentation.


git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1578182 13f79535-47bb-0310-9956-ffa450edef68