Port L-BFGS from Lua optim

Author: apaszke

docs/source/optim.rst

@@ -106,6 +106,8 @@ Algorithms
     :members:
 .. autoclass:: ASGD
     :members:
+.. autoclass:: LBFGS
+    :members:
 .. autoclass:: RMSprop
     :members:
 .. autoclass:: Rprop

test/optim/compare.sh

@@ -1,5 +1,5 @@
 
-# th test.lua > lua.out
+th test.lua > lua.out
 python3 test.py > python.out
 
 diff lua.out python.out >/dev/null 2>&1