* changed direct access of timestamp field to use getTimstamp() instead inside of calculateElapsedTime.

* Added support to the tomcat Server adaptor for correctly getting request start time. (Includes additional dependency on tomcat-coyote)
* Update layouts.html to document the addition of elapsedTime/D to the pattern support for IAccessEvent
* Modified AccessEvent.java to calculate the elapsedTime at construction of the event, instead of repeatedly in the getter.  This allows the value to be more easily seen in a debugger, and cleans up the code slightly.

Imports of Jetty and Tomcat packages are optional as you normally can not satisify both (typically there is either Tomcat or Jetty present as OSGi web container).

upped pom version to 1.0.7-SNAPSHOT

- refactoring of Jetty related test cases