_highest_parent_ now follows the tree, dK_dX > gradient_X, added update_grads_variational to linear, bgplvm for new framework
Merge branch 'params' of github.com:SheffieldML/GPy into params

Conflicts:
	GPy/core/parameterization/param.py
	GPy/core/parameterization/parameter_core.py
	GPy/core/parameterization/parameterized.py