Add column collation support for SQL Server

Fix SchemaManagerFunctionalTestCase composite foreign keys test

Correcting code example

Choose between TINYBLOB, BLOB, MEDIUMBLOB and LONGBLOB based on the length of the field.
Behaves the same way as the TEXT type declaration.

This should be 65535 (2 ^ 16 - 1) in stead of 65532.
Modified docblock to show the max lengths.

Add SQL Server 2012 platform

fix SQLServerPlatform locking hints

Fix SQLServerPlatform regular expression SQL

Remove deprecated getShowDatabasesSQL() from Platforms

Add SQLServerPlatform supports schemas

Removed outdated methods in DatabasePlatformMock.

Guid type requires SQL typehint comment

Fix wrong class names in SQLAzureFederationsSynchronizer

Sqlserver limit