[kern psi2] added flag for returning psi2 in N, not used yet, see #139
[datasets] deng et all, labels revisited
[cacher] now taking over the attributes from cached functions, such as docstring
[whitespaces]
Merge branch 'devel' of github.com:SheffieldML/GPy into devel
[vardtc] missing data handling and stochastic update in d