DDC-1266 - Fixed bug where one sequence is dropped multiple times and extended that logic to tables and constraints

Fix bug in DropSchemaSQLCollector dropping tables before sequences which can cause constraint errors

DBAL-54 - Fix sequence drop executed before tables, however sequences mostly depend on tables. Also clean up several test-failures on MSSQL tests and  Oracle Index detection.

[2.0][DDC-92] Fixed. Patch provided by Christian Heinrich. [DDC-274] Started some method renaming. [DDC-142] Fixed (join column names and discriminator column names dont support quoting) [DDC-258] Fixed.

[2.0] DDC-214, DDC-303, DDC-304 - Fix several errors with Schema Inference from Database and Metadata and Comparisons, aswell as related bugs in DatabaseDriver. DDC-305 - Abstracted TRUNCATE command for all platforms.

[2.0] DDC-169 - Introduced handling of schema / database case-sensitivity differences and to allow compability between different platforms.

[2.0] - DDC-169 - Added DropSchemaSql Visitor - Refactored Visitor package a bit, however its still not very appealing to have that much use statements cluttered in the code