[DBAL-335] Fix nasty bug in MasterSlaveConnection, connecting and writing to slave when using keepSlave option.

Set default session value for NLS_NUMERIC_CHARACTERS (Bugfix for DDC-2013)

Change default MySQL table collation to utf8_unicode_ci

params not passed from execute to logger

When parameters are passed to Doctrine\DBAL\Statement::execute, they are not passed to any enabled logger(s).

Default table collation changed to `utf8_unicode_ci`, as it handles properly a much wider array of characters (Cyrillic, for example) at a generally negligible cost of performance.

Bugfix DDC-2013 - Default Session Value ".," for "NLS_NUMERIC_CHARACTERS". This is needed because Oracle uses other characters for decimal separation depending on the servers locale

Fixed mini-typo

Small test fixes for PostgreSQL

Based on whether we are on 32 or 64 bit platform, postgres will return a string or an int for the expected php type of a bigint that is > 32 bits.

Use dropAndCreateDatabase schema manager function in test initialization instead of individual versions of each.

Fix DDC-1978

ExpressionBuilder in and notIn methods

Changed 'implements' by 'extends' on SQLAzureFederationsSynchronizer

Changed 'implements' by 'extends' because AbstractSchemaSynchronizer is a class not an interface (and Eclipse PDT shows a warning that say that "The type SQLAzureFederationsSynchronizer must implement the inherited method processSqlSafely, processSql" but those methods are already implemented on AbstractSchemaSynchronizer).

Fixed some phpdoc

Added a missing method in the Constraint interface

Fix unsigned columns in MySql

Unsigned column properties were never set. In consequence all migrations diff were trying to change the column definition when it was already changed.