Deep copy

[liu15]

Add DEEP_COPY_RAW_PTR option for managed array initialization from raw pointers

[adayton1]

Can you add a release note?

[dtaller]

This MR was fine, but I do have two questions. Why did you make deep copy a compile time option instead of an argument, as for example

host_device_ptr<T>(T* from, size_t size, const char * name. bool deepCopy=false)

Also, what are the use cases for this?

[liu15]

This is mainly to create a version of the code that does not rely on XNACK when using a single memory space (XNACK allows CPU pointers to be accessed from the GPU). This function is basically our memWrap and if you wanted to always deep copy, you wouldn't use this constructor.