Change if to ternary operator

## Two expected scenarios
### Return

``` csharp
if (something)
    return a;
else
    return b;
```

Becomes:

``` csharp
return something ? a : b;
```

If necessary, cast `a` to the expected value;
### Attribution

``` csharp
if (something)
    v = a;
else
    v = b;
```

Becomes:

``` csharp
v = something ? a : b;
```