Update cloud-services-how-to-scale.md

The third paragraph contains two duplicate words so I removed them.
... but are but are turned on or turned off from an availability ...
Typo in layer name and index

+ forgotten brackets escaping
Add content for testing scenarios.
add link to unit testing in Visual Studio Online article
New art for CD testing
Merge branch 'AUX491' of github.com:Azure/azure-content-pr into cdtest
initial writing
Merge branch 'DailyPub' of github.com:Azure/azure-content-pr into vnetupdate
adding a note in features about vnet support, fixing a ' character that wasn't rendering correctly
more writing for vnet
adding include for note about custom provisioning
updating stuff for vnet
fixing merge issue
revised per top-ten analysis
NH-aspnet-backend-ios-notify-user fix
Merge remote-tracking branch 'upstream/DailyPub' into DailyPub
nh ios notify user images fix
nh ios notify user images fix
notify-user fix
Merge remote-tracking branch 'upstream/DailyPub' into DailyPub