Update httpLastModified from the feed response

[kesselb]

Fix #588

LastModified is used (in a feed context to see if a user edited a feed). httpLastModified to store the last-modified response from the source.

Without the patch the http_last_modified value is not longer updated hence updates for feeds will always request the whole data.

news/lib/Db/NewsMapper.php

Lines 39 to 49 in becce6b

	public function update(Entity $entity)
	{
	$entity->setLastModified($this->time->getMicroTime());
	return parent::update($entity);
	}
	public function insert(Entity $entity)
	{
	$entity->setLastModified($this->time->getMicroTime());
	return parent::insert($entity);
	}

last_modified seems to be a field to track changes for a record. http_last_modified is the field for the lastmodified timestamp.

[SMillerDev]

Tests are failing. Please fix those