Added abstract method getPrimaryKey for Crud classes
Changed Crud\Table::read/update/delete signature - $primary is array
Changed Crud\Table::addError signature
Added support assoc array for find elements
Added method Db\Row::afterRead hook for prepare data after retrieve it from Db
Fixed access level
Fixed codestyle
Merge pull request #147 from AntonShevchuk/master

Fixed support tables with multicolumn PK