Check "sha" is not empty as well as checking for null

In my working copy the "sha" var was empty, not null and was throwing an exception.
Change config modules to not be inherited by child apps

Otherwise, things blow up since they don't have the same bin folder
Adjust Kudu to prefer alternate variable name when detereminng site name.
Fixes issue #741.
Adding support for NuGet 2.7 package restore
Merge branch 'S23'
Updating Kudu to use NuGet 2.7 restore
make public Kudu drop ready for private SiteExtension
Redirect GET /deploy requests to the Kudu root
Added Server Variables to env.aspx
disable test hg pull from github due to unreliable error
Add instance id to diagnostic file names
Fixes #748
Get rid of obsolete SCM_SITE_BUILDER_FACTORY setting.