Patch for Review: JvGetStringUTF and JvTempCString

[Tom Tromey]

>>>>> "Mohan" == Mohan Embar <gnustuff@thisiscool.com> writes:

Mohan> ...are like fingernails on a blackboard for me, and they're not
Mohan> limited to just natFile*.cc. I like the idea of encapsulating this
Mohan> by a class and doing any necessary cleanup in the destructor.

Ok, sorry for the diversion there.  It does make sense to have this
around.  Let's put it in jvm.h.

Tom