Correct return types.
Also adjust return types for _authRequired()
Fix security component failing on csrf tokens.

The `_csrfToken` field should be ignored when validating post data.

Refs #5100
Merge pull request #5101 from cakephp/issue-5100

Fix security component failing on csrf tokens.
Due to configuration merging, users were not getting the help exception for login
Merge pull request #5090 from cakephp/3.0-returntypes

Correct return types.
Fix coding standard.
Merge pull request #5102 from cakephp/3.0-fix-exception

Actually showing exception for warning users about username
Update ConnectionTests
- Update the applyFullTableName tests :
 . Changed a table name to a more conventional name
 . Used the $condition var
 . Added more complex cases
- Added tests for the Connection::isTableNamePrefixed() method
- Added tests for Connection::rawTableName() method
- Added tests for Connection::fullFieldName() method
Fixes the Database\Query::hasTableAlias() method
The method only worked when a field name (e.g. table.field) was given. A string (meaning a single table name) without a dot would always return false, which was wrong.
Tests were also added.
Remove a useless variable
Mixes the indexation of tables aliases in the Query with a call to Query::join()
Use '=== false' instead of '!$var'
Merge remote-tracking branch 'upstram/3.0' into 3.0-connection-prefix