Changed ApplicationRoot::setClipboardContents() to a raw pointer.

It doesn't manage the reference count for the object because it takes a copy.
Removed deprecated Box metadata methods.

The standard Metadata API should be used instead.
Updated OSLImageTest for improved dirtiness signalling.

It should have been updated as part of 2d0ab75b2a27251602379671cd0c7371ad995204.
Updated for IECore::IntrusivePtr -> boost::intrusive_ptr change.

This is necessary for compatibility with the latest Cortex version.
Added missing wrapper for NodeGadget::nodule() overload.
Fixed ParameterHandler API to use raw pointers where appropriate.
Fixed ParameterisedHolder API to use raw pointers where appropriate.
Fixed Gadget API to use raw pointers where appropriate.
Fixed Nodule API to use raw pointers where appropriate.
Merge pull request #902 from johnhaddon/boostIntrusivePointer

Boost intrusive pointer