Update BigSwitch Name to its correct name

Update Neutron documentation and code comments to replace
"BigSwitch" name to "Big Switch"

Closes-Bug: #1299145
Change-Id: I7c14f6170871b361c8929898ee6af5d1a1f41714
(cherry picked from commit 408ef55d4ef1a9d246571511203ab337ba5346c6)
NSX: Fix pagination support

Add pagination support to the base plugin,
leaving the service plugin unaltered.

Minor tweaks to the UT where required to
avoid intermittent failures caused by random
ordering.

Closes-bug: 1295854

Change-Id: I03e9e104967716046909d6120426e879f714a5c8
(cherry picked from commit 16ce0ae2c2b50b4317cdb95e62246d805b3d76a9)
Merge "Update BigSwitch Name to its correct name" into milestone-proposed
Merge "NSX: Fix pagination support" into milestone-proposed