Update links in Readme

Fixed SQL Server Platform NULL declaration

Problem with sequence names, PostgreSQL and MixedCased schemas

fixed typo for enabling DEFERRED support

[DBAL-374] Fix issue with column quoting in primary keys, fixing this in indexes in general is much more complex as the code is messy.

Fix SQLServerPlatform adds unique constraint to ADD PRIMARY KEY statement

This will only happen when adding primary keys via ALTER TABLE

default table option not working

- Fixing issue, key name corrected

[MySQL] Fixed bug with comments not adding quotes for tables

Remember to close temporary connection in PostgreSqlSchemaManager::dropD...

Remember to close temporary connection in PostgreSqlSchemaManager::dropDatabase() and PostgreSqlSchemaManager::createDatabase()

Add schema changes for length for postgres

Added exit code for dbal:reserved-words command

Delete always content from table master_slave_table between tests.

Removed Unsigned Integer Support in SQL Server

Optimize autoload prefix in composer.json

Fix dropping foreign key multiple times with test

In some cases the Comparator class returns multiple drops for the same foreign key.
Specifically, in case you have two tables, A & B, with A having a foreign key FK
referencing B, if you drop table B, the resulting diff shows this FK twice,
once on the diff->orphanedForeignKeys array as we're deleting B, and another on
the diff->changedTables array as table A is also being modified. As a result of this you
get the DROP FOREIGN KEY instruction twice in the final SQL.

By having more specific autoload prefixes it is possible to reduce the number of stat calls made.