Separating power ground from control ground
Yes the power ground and control ground are connected to eachother, but allmost all switched mode converters like the TPS61030 need these grounds separated in the sense that the large currents flowing through the power ground must not disturb the control ground. Imagine what happens when a large current flows through power ground, the (small) series resistance of the PCB tracks cause some voltage drop. You do not want this voltage drop to be "seen" by the circuits connected to the control ground. So what you want to do is to give the control ground it's own separate track to a common ground piont. You should connect the ground from your power source also to this point.
If you have an old computer power supply lying around, have a look inside ! You will notice that on the PCB there will be a large ground but smaller ground tracks branching off from that ground. It is called a "star ground".