Added a new utility class that I have wanted for a while. The CleanUp

class is a templatized class that allows you to have a cleanup function called
on a data value of type T when the value is set or when the object goes
out of scope. It has support for very rudimentary invalid value detection that
can be enabled by using the appropriate constructor. 

Anyone with template experience that can see ways of improving this class
please let me know. The example code shows a few typical scenarios in which
I would like to use it. It is currently coded with simple type T values
in mind (integer file descriptors, pointers, etc), but I am sure some 
specialization might help out the class for more complex types.

There is a lot of documentation including examples in the CleanUp.h header 
file. 

llvm-svn: 109239