Added NuGet.Jobs.Common class library to be used by all the jobs
1) This contains the TraceLogger which must be used by all the jobs.
Because, when using WebJobs, logs from all the jobs get written to the
same file. So, in order to differentiate, a prefix is added to each log
2) Contains TraceEventListener to redirect logs from EventSource to Trace
3) Contains Configuration class which handles common things like maintaining
known configuration settings such as SqlGallery, StorageGallery and so on

Also, added 1 continuous job, Catalog.Updater, which does nothing yet,
but, simply uses NuGet.Jobs.Common and runs a while loop
1. Updated environment variables to be all caps with underscores
2. Tested that logging works on the CatalogJob which does nothing yet
3. Tested that configuration retrieval works on CatalogJob
4. Also, tested that the job runs successfully as a webjob,
when all the references are zipped up and uploaded