fixed FileValidator after UploadedFile refactoring

fixes #845
updated php doc
moved MSSQL specific property to mssql TableSchema
doc fix.
fixed docs in db Schema classes
Merge branch 'master' of github.com:yiisoft/yii2

* 'master' of github.com:yiisoft/yii2:
  doc fix.
Enhanced the default implementation of Model::scenarios() to return all scenarios found in rules().
fixed typo