Converted tabs to spaces using `expand -t 4`

Maybe there's a better way, hacked this up to call `expand` on every file and strip trailing whitespace:

```
import os, os.path

def fix_file(path):
    print path
    tmp_path = "%s.tmp" % path
    os.system("expand -t 4 <%s >%s.tmp" % (path, path))
    f = open(path, "w")
    for line in open(tmp_path):
        line = line.rstrip()
        f.write("%s\n" % line)
    f.close()
    os.remove(tmp_path)

for root,dirs,files in os.walk('.'):
    for file in files:
        path=os.path.join(root,file)
        if path.endswith('.l') or path.endswith('.h') or path.endswith('.c'):
            fix_file(path)
```