sample tries to get model.test_value too now
fixed issue with lasso example
oops actually fix that problem
refactor len on ListArray
Added support for partial specification of start values
Tweaks to start in sample; updated disaster_model.py to use partial initialization
Fixed sampling failures with new start value handling
Fixed sample for scenarios when both start values and a NpTrace object are passed.
Merge pull request #286 from pymc-devs/jsalvatier

Let sample try to use model.test_point