Add rollers control loop.

The rollers are a separate control loop because Austin wanted
Comran to get practice writing them.
This change contains modifications that Comran made to the rollers
control loop. There was a lot of cleaning up and fixing by me
as well.

Change-Id: I3d012fb8a9652c0b85ed27f5d23fe7d63bb977ce
diff --git a/bot3/control_loops/rollers/rollers_main.cc b/bot3/control_loops/rollers/rollers_main.cc
new file mode 100644
index 0000000..75d2cc6
--- /dev/null
+++ b/bot3/control_loops/rollers/rollers_main.cc
@@ -0,0 +1,11 @@
+#include "bot3/control_loops/rollers/rollers.h"
+
+#include "aos/linux_code/init.h"
+
+int main() {
+  ::aos::Init();
+  bot3::control_loops::RollersLoop rollers;
+  rollers.Run();
+  ::aos::Cleanup();
+  return 0;
+}