Honestly, the recent violence just seems like more of the same. There was just an election, that's the reason for the slight uptick in violence.
Certainly the civil war never really "ended" as such. However, while I haven't been following this terribly closely for a while now, my understanding was that, for the last several years at least, the mainstream Sunni leaders were participating in the political process. If I'm understanding the situation correctly, most of the violence in the last few years has been killings by various rogue militias or jihadi groups.
As I'm reading what's been happening there this week though, the violence now seems to have a very different character. There's been an Arab Spring-esque Sunni protest movement for several months now, which has now led to violent clashes with the government and things seem to be in danger of spiralling out of control. Read Wikipedia's entry on the "Sunni uprising" for a recap:
http://en.wikipedia.org/wiki/2012–13_Iraqi_protests#Sunni_uprising
Also, what's being reported on other news sites:
http://www.npr.org/blogs/thetwo-way/2013/04/27/179462354/iraqs-sunnis-form-tribal-army-as-sectarian-violence-buildsEDIT: Oh yeah, and not to be too alarmist, but as I mentioned, things aren't great in Lebanon either:
http://www.reuters.com/article/2013/04/26/us-syria-crisis-hezbollah-idUSBRE93P09720130426
