Update Sphinx version and versioning process

- Updated to newer Sphinx version
- Changed to use doc8 to check .rst files
- Added a dictionary (dict.txt) and spellchecking
- Reformatted and fixed issues that were found in the content

Change-Id: If7b35e01ee8be25dbbd1ecd0e67b264aa6cc2a94
diff --git a/dict.txt b/dict.txt
new file mode 100644
index 0000000..59ef6e7
--- /dev/null
+++ b/dict.txt
@@ -0,0 +1,36 @@
+Accton
+Edgecore
+Inventec
+Tofino
+Whitebox
+addr
+bgpd
+blackholing
+decap
+dhcp
+dhcprelay
+dst
+encap
+eth
+ethType
+gw
+inexternal
+mcast
+mpls
+multipath
+netcfg
+ofagent
+ofagentd
+ofdpa
+patchset
+pingall
+privkey
+rst
+uboot
+unconfigured
+virtualenv
+vlan
+vlanId
+vlans
+vtysh
+withvlan