remove deprecated code (#2781)

* move deprecated code to `legacy` subfolder

* add to release notes

* add note for OPVI

* fix imports

* remove old advi

Author: ferrine

RELEASE-NOTES.md

@@ -27,6 +27,11 @@
 - Fixed `sample_ppc` and `sample_ppc_w` to iterate all chains(#2633, #2748)
 - Add Bayesian R2 score (for GLMs) `stats.r2_score` (#2696) and test (#2729).
 - SMC works with transformed variables (#2755)
+- Speedup OPVI (#2759)
+
+### Deprecations
+
+- Old (`minibatch-`)`advi` is removed (#2781)
 
 
 ## PyMC3 3.2 (October 10, 2017)

pymc3/variational/__init__.py

@@ -1,6 +1,3 @@
-from .advi import advi, sample_vp
-from .advi_minibatch import advi_minibatch
-
 # commonly used
 from . import updates
 from .updates import (