Distribute tabulate as part of Synergy

Synergy depends on the python tabulate package. However, it is not
available as a system package for both CentOS 7 and Ubuntu 14.04.

In this commit we opt for the following solution: don't mark
tabulate as a dependency when building synergy system packages,
instead we provide the tabulate package as part of Synergy.

DocImpact
Change-Id: I76018e1ba27de8ad47b59c85baad2c2d06f03398
Sem-Ver: bugfix

LICENSE_third-party.md

@@ -0,0 +1,23 @@
+tabulate
+========
+
+Copyright (c) 2011-2014 Sergey Astanin
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

requirements.txt

@@ -8,6 +8,3 @@ eventlet
 oslo.config
 python-dateutil
 requests
-
-# Packages not available as system packages (rpm or deb)
-tabulate

tox.ini

@@ -32,4 +32,4 @@ commands = oslo_debug_helper {posargs}
 show-source = True
 ignore = E123,E125
 builtins = _
-exclude=.venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build
+exclude=.venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build,synergy/client/tabulate.py