v2.15.1.0

Update for Stan 2.15.0

• Finally expose ADVI (issues #19, #28)
• fixed/document issues #26, #31, #32

v2.7.0.0

Update for Stan 2.7.0

• Add Aki Vehtari's Pareto smoothed importance sampling leave-one-out (PSIS-LOO) cross-validation package
• fixed/document issues #7, #10, #12

v2.6.0.0

Update for Stan 2.6.0

• fixed unit tests for removed stan example models dir
• fixed issue #2, workaround for int32 limitation
• ENH: peek() method for reading partial samples