civil war has already begun in agents of shield.
after skye got her powers, coulson put her in "the retreat". the same retreat in which steve rogers (captain america) was kept when he got out of his long sleep. on the wall of that house we saw this, a big punch, signs of roger's mental torture because of living in a prison for super powered people??
and its made by Bruce banner, our very own THE BIG GUY.
and the coup d'etat thats going on in the agent of shield is because "the new shield's new commander" want to know where fury hid all of his toys i.e. super powered people. he wants to regulate them, superhuman registration act??
Rogers has seen the prisons first hand that's why he is gonna oppose it.
and if banner helped shield made these retreats, it is safe to assume that tony stark is already participating in it and they both are standing against cap and we will be seeing hulk in civil war too.
we are gonna see iron man vs hulk in age of ultron, be prepared for hulk vs cap in civil war.