Allow category to be null in Azure SQL listener

Another null category fix
Add example SQL script for setting up the Azure SQL table
Updated NuGet release
Ensure the Sql Azure connection is open before logging
Improving documentation (still needs a lot of work!)
Incrementing NuGet version
Solution rename

Namespace fixes
NuGet package rename
Minor documentation cleanup
Adding a primary key to the example table script for azure sql
Documentation improvements

doc
NuGet bump / NuSpec improvements