HTTPS changes to support client authentication

Hi - I emailed this to the dev list recently:

http://markmail.org/search/?q=list%3Aorg.codehaus.sonar.dev+clientauth#query:list%3Aorg.codehaus.sonar.dev%20clientauth+page:1+mid:6zl4uy2xmtwsckfx+state:results

I think this is fairly straightforward - just passthroughs from the sonar properties to the Tomcat server config.

Please let me know if you have any questions. This is my first time sending a pull request on github and totally appreciate any feedback :)

thanks
john