README: Add 2.7, drop 2.5

CS bump to 4.0, imports for global functions & constants

Add tests for column collation to prove it works

Allow dynamic intervals in DATE_ADD & DATE_SUB for SQLite

DateIntervalType (negative support) resolves doctrine/dbal#2578

Improve handling of schemas in SQL Server >= 2008

Drop PCRE x modifier in SqliteSchemaManager (#2885 rework)

Connection parameters are cached hashed

Start SQL Server using a synchronous command to avoid intermittent login failures

Added badges for AppVeyor

See https://github.com/doctrine/dbal/pull/2617#discussion_r177250225.

fix typo

Set Appveyor to use PHP 7.2

Following a working cache example https://github.com/morozov/diff-sniffer-core/blob/master/.appveyor.yml

Test SQL Server 17 on Travis

Testing of MSSQL on Windows with AppVeyor

PHPUnit 7