Fixed GLM cross validation (just 1 and 0 swapped in scoring)
Update in RPC.call:

a) added assertion that passed DTask has no completer set (it would never be called!)
b) if executing on local, add completer which will mark the task done.
c) changed block() call to not to have special case for local execution (should be handled by the added completer).
Updated GLM2 xvalidation to be distributed on remote nodes.
Merge branch 'master' of github.com:0xdata/h2o