refactoring and cosmetics:

- renamed rate→rate2, rate_once→rate, various variables
- separate functions for
  - splitting training/validation data and calculating epoch size
  - reconfiguring the model when mapping has changed
  - text generation (also moved from scripts.run)
  - best path decoding (also moved from wrapper.rate)
  - history clustering
- changed ordering of functions
- raise pylint happiness
- fix random degradation for underspecification

Author: bertsky

.pylintrc

@@ -8,6 +8,7 @@ disable =
     too-many-locals,
     too-few-public-methods,
     too-many-branches,
+    too-many-lines,
     too-many-statements,
     too-many-nested-blocks,
     too-many-instance-attributes,
@@ -21,4 +22,4 @@ disable =
 no-space-check=empty-line
 
 # allow non-snake-case identifiers:
-good-names=x,y,n,i,j
+good-names=x,y,z,zs,c,n,h,i,j