added docstrings to helper functions

Dear Rohit,

I added some additional docstrings to your code. We should not need unit tests for this, but when I tried running them anyway, this happened:

```python
~/repos/neonx $ python setup.py test
running test
running egg_info
writing requirements to neonx.egg-info/requires.txt
writing neonx.egg-info/PKG-INFO
writing top-level names to neonx.egg-info/top_level.txt
writing dependency_links to neonx.egg-info/dependency_links.txt
reading manifest file 'neonx.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
writing manifest file 'neonx.egg-info/SOURCES.txt'
running build_ext
Traceback (most recent call last):
  File "setup.py", line 49, in <module>
    test_suite='tests',
  File "/home/arne/anaconda/lib/python2.7/distutils/core.py", line 152, in setup
    dist.run_commands()
  File "/home/arne/anaconda/lib/python2.7/distutils/dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "/home/arne/anaconda/lib/python2.7/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/home/arne/anaconda/lib/python2.7/site-packages/setuptools/command/test.py", line 138, in run
    self.with_project_on_sys_path(self.run_tests)
  File "/home/arne/anaconda/lib/python2.7/site-packages/setuptools/command/test.py", line 118, in with_project_on_sys_path
    func()
  File "/home/arne/anaconda/lib/python2.7/site-packages/setuptools/command/test.py", line 164, in run_tests
    testLoader = cks
  File "/home/arne/anaconda/lib/python2.7/unittest/main.py", line 94, in __init__
    self.parseArgs(argv)
  File "/home/arne/anaconda/lib/python2.7/unittest/main.py", line 149, in parseArgs
    self.createTests()
  File "/home/arne/anaconda/lib/python2.7/unittest/main.py", line 158, in createTests
    self.module)
  File "/home/arne/anaconda/lib/python2.7/unittest/loader.py", line 130, in loadTestsFromNames
    suites = [self.loadTestsFromName(name, module) for name in names]
  File "/home/arne/anaconda/lib/python2.7/unittest/loader.py", line 103, in loadTestsFromName
    return self.loadTestsFromModule(obj)
  File "/home/arne/anaconda/lib/python2.7/site-packages/setuptools/command/test.py", line 35, in loadTestsFromModule
    tests.append(self.loadTestsFromName(submodule))
  File "/home/arne/anaconda/lib/python2.7/unittest/loader.py", line 100, in loadTestsFromName
    parent, obj = obj, getattr(obj, part)
AttributeError: 'module' object has no attribute 'test_neo'
```

Any ideas on this?

Kind regards,
Arne