Change default distribution to jar

[fthamura]

Change default distribution to jar, and put how to make war in wiki, jar.original explanation in wiki

[dianw]

IMHO, there are 2 advantage of using executable war

• It's executable! Just type java -jar yama.war
• It's also traditional deployable war file, if you want to use -let's say- weblogic instead of embedded jetty just deploy the exact same war without any modification