Rebase Ray on latest arrow (remove numbuf from Ray). (#910)

* remove some stuff

* put get roundtrip working

* fixes

* more fixes

* cleanup

* fix tests

* latest arrow

* fixes

* fix tests

* fix linting

* rebase

* fixes

* fix bug

* bring back libgcc error

* fix linting

* use official arrow repo

* fixes

doc/source/conf.py

@@ -20,7 +20,6 @@ import shlex
 import mock
 MOCK_MODULES = ["pyarrow",
                 "pyarrow.plasma",
-                "ray.numbuf",
                 "ray.local_scheduler",
                 "ray.plasma",
                 "ray.core.generated.TaskInfo",

doc/source/installation-troubleshooting.rst

@@ -1,26 +1,24 @@
 Installation Troubleshooting
 ============================
 
-Trouble installing Numbuf
+Trouble installing Arrow
 -------------------------
 
-If the installation of Numbuf fails, chances are there was a problem building
-Arrow. Some candidate possibilities.
+Some candidate possibilities.
 
 You have a different version of Flatbuffers installed
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Arrow pulls and builds its own copy of Flatbuffers, but if you already have
 Flatbuffers installed, Arrow may find the wrong version. If a directory like
-``/usr/local/include/flatbuffers`` shows up in the output when installing
-Numbuf, this may be the problem. To solve it, get rid of the old version of
-flatbuffers.
+``/usr/local/include/flatbuffers`` shows up in the output, this may be the
+problem. To solve it, get rid of the old version of flatbuffers.
 
 There is some problem with Boost
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 If a message like ``Unable to find the requested Boost libraries`` appears when
-installing Numbuf, there may be a problem with Boost. This can happen if you
+installing Arrow, there may be a problem with Boost. This can happen if you
 installed Boost using MacPorts. This is sometimes solved by using Brew instead.
 
 Trouble installing or running Ray