F/java dest

Implemented java destination, which get a class_name and class_path.

The destination class has to implement three methods: 
 - public boolean init()
 - public void deinit()
 - public boolean queue(String message)
(and it must have a default constructor)
init is called from destination driver's initialization method
deinit is called from destination driver's deinitialization method
queue method is called when a message is available for processing for the destination.
The string parameter of the queue method is the template formatted message.
The template can be set in the configuration, the default template is:
"$ISODATE $HOST $MSGHDR$MSG"

In my test environment (Ubuntu Trusty), 
```find /usr/lib/jvm/java-7-openjdk-amd64/ | grep jni_md``` returns two lines:
```
/usr/lib/jvm/java-7-openjdk-amd64/include/linux/jni_md.h
/usr/lib/jvm/java-7-openjdk-amd64/include/jni_md.h
```
which messes up the Makefile. I restricted the output for only the first line:
```JNI_MD_INCLUDE_DIR=`find $JNI_HOME -name "jni_md.h" | sed "s/\(.*\)jni_md.h/\1/" | head -n 1```
and now it compiles flawlessly.