Refactored shader nodes so that the plug to store the shader name is managed by the base Shader class.
Fixing ArnoldShader::shaderHash() - I'd removed the implementation but not the declaration.
Fixing more problems with the previous commits. Muppet.
RenderManShader reloading.

RenderManShader::loadShader() may now be called passing keepExistingValues=true, to update the node status when a shader has changed on disk. This is done automatically after loading a script, so that the nodes should always be in sync with what's on disk. Also added support for min and max shader annotations which are supported for float, vector, point, normal and color shader parameters. Still need to add UI elements to expose the reloading to users.
RenderManShader node no longer builds plugs for output parameters.
Merge branch 'master' of https://github.com/johnhaddon/gaffer into shaderReloading

Conflicts:
	src/Gaffer/VectorTypedParameterHandler.cpp
Shader name and reload UI.
Merge pull request #135 from johnhaddon/shaderReloading

Shader reloading