Use the java.class.path property for dynamic class loading

[dzagieboylo]

Runtime class loading has been implemented in class.cpp; however it will only search the linked libjdk or libjvm for the class binary. The jni_FindClass function is supposed to load the desired class from the java.class.path directory on the host file system if not found elsewhere. We should support his functionality as well.

This requires 2 things:

1. a means for access the system properties from our runtime code (they are accessible from java via the System.properties object)

2. Code to search the file system for JLang-compiled classes and load them into the current execution