Preparations for coming features (#1818)

* removed unused convert_tz code
* added timestampable listener to support automatic updates of change columns
* added modified_at, billable and category timesheet fields
* new timesheet API query parameter modified_after

src/Doctrine/Query/Sqlite/ConvertTz.php

@@ -1,57 +0,0 @@
-<?php
-
-/*
- * This file is part of the Kimai time-tracking app.
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-namespace App\Doctrine\Query\Sqlite;
-
-use Doctrine\ORM\Query\AST\Functions\FunctionNode;
-use Doctrine\ORM\Query\Lexer;
-use Doctrine\ORM\Query\Parser;
-use Doctrine\ORM\Query\SqlWalker;
-
-/**
- * This is just a fake, as SQLITE does not support this by now.
- */
-class ConvertTz extends FunctionNode
-{
-    protected $dateExpression;
-
-    protected $fromTz;
-
-    protected $toTz;
-
-    /**
-     * {@inheritdoc}
-     */
-    public function getSql(SqlWalker $sqlWalker)
-    {
-        $fieldName = $sqlWalker->walkArithmeticExpression($this->dateExpression);
-        $fromTz = $sqlWalker->walkStringPrimary($this->fromTz);
-        $toTz = $sqlWalker->walkStringPrimary($this->toTz);
-
-        return sprintf('%s', $fieldName);
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function parse(Parser $parser)
-    {
-        $parser->match(Lexer::T_IDENTIFIER);
-        $parser->match(Lexer::T_OPEN_PARENTHESIS);
-
-        $this->dateExpression = $parser->ArithmeticExpression();
-        $parser->match(Lexer::T_COMMA);
-
-        $this->fromTz = $parser->StringPrimary();
-        $parser->match(Lexer::T_COMMA);
-
-        $this->toTz = $parser->StringPrimary();
-        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
-    }
-}