Timing: about twice as fast
```
opt: 10.5315260887
fs: 21.0611829758
```

is the output of

```py
from timeit import timeit

setup = """
import os

import mne

data_path = mne.datasets.sample.data_path(download=False)
subjects_dir = os.path.join(data_path, 'subjects')

aparc = mne.labels_from_parc('fsaverage', 'aparc', 'lh', regexp='lingual',
                             subjects_dir=subjects_dir)[0]
label = aparc[0]
"""

code_opt = """
mne.split_label(label, 2, subjects_dir=subjects_dir, fs_like=False)
"""

code_fs = """
mne.split_label(label, 2, subjects_dir=subjects_dir, fs_like=True)
"""

print "opt: %s" % timeit(code_opt, setup, number=1000)
print "fs: %s" % timeit(code_fs, setup, number=1000)
```