Add SQL Server 2012 platform
revert SQLServerPlatformTest for now as it uses SQLServer2008Platform and thus fails
add dedicated SQLServer2012PlatformTest and fix getSequenceNextValSQL in platform
Add dedicated keywords list for SQL Server 2012
Fix typo and version number in keywords list
Remove SQL Server 2012 specific keywords from base SQL Server keywords list.
Merge pull request #260 from deeky666/add-sql-server-2012-platform

Add SQL Server 2012 platform