Switch around ordering of question combining

This has the advantage that for some ModulusInformation object m and
some modulus,

```
a = m.split(modulus);
m.cast_down(x);
```

is equivalent to

```
m.cast_down(x*modulus);
a = m.split(modulus);
```

This means that when using a ModulusInformation object to answer
questions, we can answer the first question without needing to know how
many questions there are.

README.md

@@ -73,5 +73,5 @@ On the first 20000 seeds, we have these average scores and win rates:
 |---------|---------|---------|---------|---------|
 | cheat   | 24.8594 | 24.9785 | 24.9720 | 24.9557 |
 |         | 90.59 % | 98.17 % | 97.76 % | 96.42 % |
-| info    | 22.3249 | 24.7278 | 24.8919 | 24.8961 |
-|         | 09.81 % | 80.54 % | 91.67 % | 91.90 % |
+| info    | 22.3316 | 24.7246 | 24.8892 | 24.8969 |
+|         | 09.81 % | 80.38 % | 91.45 % | 91.94 % |

src/strategies/information.rs

@@ -29,7 +29,7 @@ impl ModulusInformation {
     }
 
     pub fn combine(&mut self, other: Self) {
-        self.value = self.value * other.modulus + other.value;
+        self.value = self.value + self.modulus * other.value;
         self.modulus = self.modulus * other.modulus;
     }
 
@@ -39,10 +39,10 @@ impl ModulusInformation {
         let original_modulus = self.modulus;
         let original_value = self.value;
         self.modulus = self.modulus / modulus;
-        let value = self.value / self.modulus;
-        self.value = self.value - value * self.modulus;
+        let value = self.value % modulus;
+        self.value = self.value / modulus;
         assert!(original_modulus == modulus * self.modulus);
-        assert!(original_value == value * self.modulus + self.value);
+        assert!(original_value == value + modulus * self.value);
         Self::new(modulus, value)
     }