Issue #258: win32lfn support in Kallithea for Windows installations (conservancy/kallithea)

[Brandon Jones]

New issue 258: win32lfn support in Kallithea for Windows installations
https://bitbucket.org/conservancy/kallithea/issues/258/win32lfn-support-in-kallithea-for-windows

Brandon Jones:

With our client installations we have the win32lfn extension installed on all client machines using TortoiseHG in Windows.  This allows us to avoid the "long filename" limitation of Windows.  It doesn't come up often, but it's there from time to time.

Here is the extension we use:
https://bitbucket.org/remleduff/win32lfn

This works fine on our client machines, but the internal version of Mercurial that Kallithea uses does not know about this extension and does not use it.

I forced the internal Mercurial version of Kallithea to use win32lfn but I got errors when I tried to create a repo group.  I'm sure given the nature of the extension that this would occur in more than one place.  Here is the error I got.


```
#!python

2016-12-06 15:31:57.694 ERROR [kallithea.controllers.api.api] Traceback (most recent call last):
  File "c:\kallithea\env\lib\site-packages\kallithea\controllers\api\api.py", line 2099, in create_repo_group
    copy_permissions=copy_permissions
  File "c:\kallithea\env\lib\site-packages\kallithea\model\repo_group.py", line 189, in create
    self._create_group(new_repo_group.group_name)
  File "c:\kallithea\env\lib\site-packages\kallithea\model\repo_group.py", line 95, in _create_group
    os.makedirs(create_path)
  File "c:\kallithea\env\lib\os.py", line 157, in makedirs
    mkdir(name, mode)
  File "c:\kallithea\env\scripts\win32lfn.py", line 193, in lfnmkdir
    pyerrno = _errmap[error]
KeyError: 5L 
```

I think it would be quite valuable if Kallithea could make use of this extension to handle support for long file names in Windows.