added support for java.util.logging (JUL)

In july we started using logentries for one of our products. We are using java util loggings (JUL) instead of log4j or logback, so we could not use your official framework. I came up with a custom handler that supports JUL. Its running in production right know and we are quite happy with the result.

This handler might reach a greater audience in your framework than in mine. Its currently hosted in raupachz/jul--ext.