Date detection : strtotime() fallback

If feed-io fails to detect the date format from the list, it tries to guess it automatically.

#87

Date injection + refactoring

This release embeds the following :

#86
#89
#90

Bugfix : fix warning message for some URLs

Fix for #84

Optional Elements full support

Fix bug : #82

Added full support of sub elements : #76

Fix Atom's author support

Merge pull request #80 from alexdebril/issue/72

Close #72 : author's properties are stored in nodes

Author support

Now the author node is correctly handled : #72
Trim XML streams to delete whitespace : #73

New date formats

Added the following date formats :

• 'Y-m-d\TH:i:s'
• '*, m#d#Y - H:i'

Ability to reset filters

Now we can reset FeedIo's filters, it's recommended to do so after each feed reading :

        $this->feedIo->read($feed->getUrl(), $feed, $feed->getLastModified());
        $this->feedIo->resetFilters();

It fixes issue #70

Fix aliases not matching upper-cased tags

Fix #68

Fix InvalidArgumentException

Test if the node is valid before accessing its first child. It prevents from InvalidArgumentException when the feed description tag is empty: