always use whitespace around statements

Right now the code is not consistent about whether or not it uses whitespace around statements. The code uses both of the following styles:

```c
if(somecond == 1) {
```

as well as

```c
if (somecond == 1) {
```

However, for function invocation the style is always:
```c
foo(arg1, arg2, ...);
```

I think it's necessary to choose a style and stick to it. I strongly recommend using spaces around the builtin statements (`if`, `for`, `while`, `switch`) to make them visually distinct from function invocation. This is the convention used in most of the C projects I've worked with in the past.