Support functions for Android's class libraries


These are VM-agnostic native functions that implement methods for system
class libraries.  All code here:

 - MUST be associated with a standard java.* class (no Android-specific stuff)
 - MUST use JNI
 - SHOULD be written in C rather than C++ (it's usually smaller and all of
   our VMs are written in C)

Some helper functions are defined in ../include/nativehelper/JNIHelp.h.

