Improved grok patterns for Java

I used logstash to parse our log files. Unfortunately this parsing failed for some special named classes and methods.

We allow the underscore character to be part of the package or the class name. This is not allowed in the grok pattern for Java classes. So I added this character to the JAVACLASS pattern.

Furthermore I have log lines containing the constructor of classes as method, which is logged as "<init>". So I introduced the grok pattern for a Java method that allows additionally to the WORD pattern the angle brackets und used that pattern in the JAVASTACKTRACEPART pattern.
@wiibaa Hello Wiibaa!
The Java object initialization method sometimes appears in log headers if the Java method writing something to the logs should be parsed. This method is named "<init>". It contains the initialization of all member variables of an object, too. So, if something happens there, you will see the Java method "<init>" in the logs and this should be parseable easily. Some more information about this object initialization method: http://www.artima.com/designtechniques/initialization4.html