[DBAL-1016] Fix explicitly quoted table identifiers in ALTER TABLE statements

Adds support for setting the charset in SQLSrv

As seen here => http://technet.microsoft.com/en-us/library/cc626307(v=sql.105).aspx

Reset date fields to UNIX epoch in TimeType.

TimeType resets date fields (i.e. unused DateTime object fields) to UNIX
epoch (1970-01-01). This makes TIME field mapping stabe (i.e. same time
will be always mapped to the same DateTime fields).

See DDC-179 (similar issue with DateType). Fixes DBAL-993.

[DBAL-1014] Support HHVM mysqli driver

Close #696

[DBAL-1009] Fix column comment lifecycle

[DBAL-1001] Fix NULL / NOT NULL clause for column alterations in Oracle

[DBAL-831] Fix explicit case sensitive identifiers in Oracle

[Documentation] Add missing quotes at the end of literal strings

[DBAL-1010] Fix renaming column with default value on SQL Server

[DBAL-1011] Fix column comments containing string literal chars on SQL Server

Fixed expanding positional parameters which do not start from 0

Add test for explicit positional parameter keys in SQLParserUtils

Changed the composer constraint to allow Common 2.5

[DBAL-774] Fix QueryBuilder parsing order of joins