Fix failing sqlserverschema tests
Change binary column type to VARBINARY(MAX).

SQL Server binary columns have a maximum length of 8000 bytes. Varbinary columns also have a maximum length of 8000 bytes. Varbinary(MAX) columns support up to 2 GB.
Fix for TestFixture to use columnName as the key for the column type array.

It was causing an issue with SqlServer and binary columns in a fixture since SqlServer is quite pedantic on how columns are bound.
Merge pull request #3557 from dakota/3.0-sqlserver

Changes to SqlServer drivers