Update all code to use real type

src/box.hpp

@@ -1,19 +1,20 @@
 #ifndef BOX_H
 #define BOX_H
 
+#include "precision.hpp"
 /**
  * Struct representing the simulation box.
  * Currently the simulation box is always assumed to be perfectly rectangular.
  * This code does not support shearing the box. This functionality may be added
  * in later.
  */
-template <typename T> struct Box {
-  T xlo;
-  T xhi;
-  T ylo;
-  T yhi;
-  T zlo;
-  T zhi;
+struct Box {
+  real xlo;
+  real xhi;
+  real ylo;
+  real yhi;
+  real zlo;
+  real zhi;
   bool x_is_periodic;
   bool y_is_periodic;
   bool z_is_periodic;